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Professor Michael A. Velbel’s presentation about the rates and rate-determining processes in natural weathering of rock-forming minerals was overall easy to follow and understandable. He is a Professor of Geological Sciences at Michigan State University, and he is also currently an associate editor of the American Journal of Science. During Dr. Murray’s speaker introduction, I was impressed to hear about him being an editor of a reknowned scientific journal.

Three new ‘things’ I learned include 1) feldspar reaction he proposed is 2-step process, instead of 1-step process as many textbooks say, and those 2-step process includes dissolving the molecules completely and forming clay afterwards, 2) Biotite Mica is a natural K source for vegetation, and it has completely different mechanism from pelspar which requires one to do matrix algebra, and 3) studying minerals and their reactions with aqueous solutions improves understanding of many phenomena on earth and elsewhere in the solar system and beyond. I also learned that

I think the presentation was pretty interesting as he focused on presenting the information that can be understood by us, instead of presenting many detailed and abstract informations about his research that can only be understood by those who have studied or researched in the same area. During the seminar, I have felt that the presenter was very experienced with his area of research and presenting scientific information to the student body.

I would describe the presentation in one short sentence to my ‘non-science’ friend or family as the following: “The presentation by Michael A. Velbel discussed about how microscopes are connected to geochemistry.”

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This installment of ChemSem had the honor of hearing Dr. Hisashi Yamamoto of the University of Chicago present on some of the studies he has undertaken in the past. Yamamoto is a world renown organic synthetic chemist with many years of experience. He’s spent many years focusing on developing the science and art of organic reaction syntheses of natural substances.

It is well known that there is much waste involved in standard synthetic organic chemistry. Solvents, catalysts, and other reagents must often be discarded after use. Futhermore, a standard synthesis of a compound generally requires a few to several reaction steps multiplying the volumes of wasted materials. Yamamoto has been focusing on reducing that waste by developing methods of single step syntheses. Though some of the reagents that he uses in his single step processes are more expensive than general reagents, and must also be discarded, the overall cost-benefit analysis shows that the economy of time and material for one step far outweighs the costs of more expensive reagents.

Much of the seminar involved the syntheses of polyketides which are valuable due to the fact that they generally are five times more biologically active than commonly occurring organic substances. Thus, a method for easily synthesizing them, could have significant ramifications on the pharmaceutical industry. Secondly, I thought it was interesting when Dr. Yamamoto pointed out as an example of waste that even the synthesis of Vitamin E which is produced in vast quantities, commonly uses large amounts of dichloromethane for production. Finally, Dr. Yamamoto used super Bronsted acids for portions of his synthesis. When asked about these, he noted that they were very useful, but had not been invented by organic chemists seeking better acids. Instead, it turns out that they were developed by the inventors of Lithium Ion batteries to increase speed of reaction.

Overall, Dr. Yamamoto did an excellent job of presenting the value of single step cascade reactions for synthesis of organic materials. If possible, this could be a very useful tool and could greatly increase the rate of discovery in chemical studies. Much of the intricate chemistry involved was difficult to grasp, but overall the presentation was well received.

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This week’s lecture was done by the famous organic chemist Hisashi Yamamoto from the University of Chicago, known for such things as the Yamamoto reagents and reactions. His presentation was fairly interesting, but it was sometimes hard to understand what he was saying. The reason I found this presentation to be interesting was the topic of the catalysts. I have always found catalysts to be an intriguing subject, and it would be nice to have more lectures on the subject.

One thing that I learned from this lecture was that it only takes a very small amount of base in a reaction or solution to kill the acid catalyst. Something that I would like to find out about is what makes cascade reactions have a one hundred percent economy. This is not typical for many things, but it is interesting that it is almost always the case with cascade reactions.

Another thing that I learned from this lecture was that for cascade reactions there are a lot of solvents and big and “bulky” reactants that are used during the processes. To me this seems like it would be very expensive, but I guess that since the reactions usually produce one hundred percent product, this may not be much of a problem.

If I were explaining the content of this lecture to one of my non-science friends I would probably describe it as a lecture about how chemists can use cascade reactions to produce different chemicals using different catalysts. As for the speaker, it was very enjoyable to have a well-known chemist lecture us, and it would be nice to have a chance to hear Dr. Yamamoto speak again, whether it be here at Andrews or somewhere else.

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Our high profile, award winning guest Hisashi Yamamoto, professor of organic chemistry at the University of Chicago, thinks of new strategies and ways to shorten the number of reactions needed to obtain a product, especially using cascade reactions (the whole reaction takes place in one pot or tube reactor) hoping for 100% atom economy, eliminating side products. His research also includes asymmetric synthesis using acid catalysts (Brønsted and Lewis acids) and the development of efficient syntheses of polyketides for production.

Biologically active polyketides compose 2% of all polyketides and naturally-derived products proved very effective as a therapeutic medicine in certain areas. Due to its highly stereoselective nature, polyketide synthesis normally consists of 50-100 steps and yield only a little amount. Yamamoto’s work researched methods of using their homemade Super Brønsted Acids and Super Silyl to improve the Mukaiyama aldol reaction. Many of the acid catalysts shown were quite bulky and very steric—the steric hindrance acts as a sort of “umbrella”, preventing other reactions from occurring. These acid catalysts proved to be more selective and powerful in reactions as well as being very efficient, needing only a small amount of the very reactive catalyst. Also, Super Brønsted acids can be almost completely recovered, making it a recyclable resource. During the Q-and-A, someone asked about super acids availability (this was the first I had heard of them as well). Apparently, they are not expensive, commercially available, and also easy to make. When Yamamoto told us that it was not organic chemists who had discovered them but the battery companies everyone had a good laugh.

Andrews University includes a number of students whose first language is not English and many of them feel quite uncomfortable speaking in front of an audience because of this. I think that Professor Yamamoto, who came to the United States after receiving his Bachelor degree in Japan, demonstrated good seminar techniques for those students. Taking his time to speak calmly and unrushed, few were the times Yamamoto stumbled over his words. Of course, perhaps it was due to his great familiarity with organic chemistry, having started teaching himself in middle school.

Laymen’s Summary of Chemistry Seminar: Professor Hisashi Yamamoto is an organic chemist who thinks that ridiculously lengthy syntheses that have low percent yields need to change. So he’s looking into super acid catalysts to improve results and massively cut down the number of steps needed to produce polyketides (which can take 50-100 steps ). He believes that the new frontier involves cascade reactions, where all the ingredients for a synthesis go in one pot or reactor tube, taking the shortcutting to a maximum.

I especially liked this interview from the ROYAL Society of Chemistry that Dr. Murray linked to us:

http://www.rsc.org/Publishing/ChemScience/Volume/2009/07/Hisashi_Yamamoto_interview.asp

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Today’s guest speaker for the chemistry seminar was Hisashi Yamamoto. He is an Arthur Holly Compton Distinguished Service Professor at the University of Chicago. He has received various awards in chemistry and published hundreds of articles, reviews, books, and journals.

The title of the presentation was “Designing Asymmetric Catalysis – Cascade Reaction for Polyketide synthesis.” Mainly, Hisashi Yamamoto explained about synthesizing catalysts, which have more power than other catalysts that have existed before. Generally, a catalyst is a chemical substance which is not consumed in the chemical reaction. However, it participates by speeding up or speeding down the reaction through reducing or increasing the activation energy of the reaction. He said that by using strong catalysts, he can reduce the amount of steps needed to make products, which also saves time, money, and materials. Also, I learned that it is important for cascade reactions to have no side products and load very low catalyst.

From his presentation, I found that most of the reactions he did occurred at very low temperature; from -78°C to 0°C. I was wondering if there were any special reasons that the temperature was very low. Does the temperature affect the behavior of the catalyst?

It was interesting that I had a chance to meet a world famous chemist and learn about his passion for his job. He said that he had never thought about having any other career except as a chemist. I want to be as passionate about my work as he is.

I would tell my friends that he is using more effective chemical substances which help speed up reactions.

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This week’s presentation speaker was Hisashi Yamamoto, a professor of chemistry at the University of Chicago. He has made an extremely noticeable achievement in acid catalysis in organic synthesis. Because it was a great opportunity to meet a world-famous organic chemist, I was very excited about his seminar.

First of all, I learned the importance of a cascade approach for organic synthesis. One of the significant topics he spoke about during the presentation was the cascade reaction of an organic compound that needs a lot of steps to be synthesized. If chemists reduce many reaction steps and synthesize the molecule in very few steps, their findings can lead to a great change. To save steps means that they can make the compound efficiently by saving materials and times. In addition, I learned about the “super Brønsted acid.” He mentioned the Mukaiyama aldol reaction, and in order to improve this reaction, he made super acid catalysts. In spite of a small amount of Brønsted acid, the super acid catalyst functions very well  in the synthesis of complex organic molecules.

Another thing I found out was that he successfully made “super silyl” group. Super silyl is so reactive and selective that it provides sufficient reactivity of silyl enol ether and is used as a protecting group in several organic reactions.

One of the questions I had during the seminar was about “chiral” Lewis acid, what chiral Lewis acid catalyst is, and how it works differently when compared to achiral acid catalyst.

I think the seminar was very interesting for me because I could learn a lot from him in terms of acid catalyzed synthetic reactions including Lewis acids and Brønsted acids. Also I would say to my ‘non-science’ friend or family that Professor Yamamoto has developed acid catalysts to improve ease and economy during organic synthesis.

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We were privileged and delighted this week to receive words from the renowned organic chemist Dr. Hisashi Yamamoto. From the start, it was evident that this was to be a stirring lecture and very engaging. Dr. Yamamoto’s love for organic chemistry came at an early age, even in high school. His journey led him to the University of Chicago where he continues his research today.

Dr. Yamamoto spoke to us on the topic of Cascade reactions and specifically in the realm of the biologically-significant polyketides. Employing the use of strong, bulky, homemade acids, Yamamoto’s team has been able to clump what used to be a 3 to 5 part series of reactions into one reaction which retains complete “atom economy,” meaning that there are no byproducts of the reaction apart from the desired product. Not only has this method been successful in yields and general economy, it has also proven to show stereospecificity in the upper 90%’s. Attributing to the economy of this process is the fact that several of the acid species were able to be recycled and reused.

Dr. Yamamoto is clearly passionate about his material, and became increasingly excited about the material as the talk progressed. All those present were engaged and enjoyed his very easy-going upfront persona. Dr. Yamamoto proved very proficient during the Q & A time, showing that he was very aware of most of the ins and outs of his research. Dr. Yamamoto achieves perfect tens in all my areas of “judgment,” which include professionalism, chemistry content and student engagement.

To the layperson, this seminar discussed how to economically make important “life” molecules in the areas of saving time and money.

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This week in seminar we were all given a very special treat: variety. Barring dentistry, mineral chemistry and geochemistry are virtually nonexistent in general, organic and biochemistry. Dr. Michael Velbel, a geochemist from Michigan State University, talked to us about different patterns of mineral erosion and other physical and molecular characteristics of minerals.

Dr. Velbel was given the challenge to connect with students who, for the most part, have not had an environmental chemistry or a geochemistry class. Some had probably never even had a lecture on the subject. I half-expected people to raise their hands and ask if this applied to Grignard reagents. Obviously, they wouldn’t do that. Dr. Velbel had a very intellectual yet friendly and approachable demeanor about him, so he easily bridged the gap of familiarity with the students. He spoke of his treks up into the hills and mountains to fetch additional data supporting the cycling of minerals in surface and ground water.

As part of his presentation, Dr. Velbel showed TEM slides demonstrating a pattern of “holes” in the solid mineral structure, indicating the location that Feldspar used to be located. He mentioned that his research included no cleaning of the samples and that they were essentially examining mud. Perhaps what Dr. Velbel will be most remembered for, however, is the slide he showed of actual atoms. Not cells, not organelles, not masses of collagenous protein, but atoms. I found this to be the most exciting part of the lecture for me. I can see why he is so fond of his beloved TEM.

Dr. Velbel stands out to me as one of the best lecturers we’ve had so far. He seemed very excited about his material and very saddened when time was up and he had to let everybody go. My judgment is as follows: 10/10 for professionalism, 10/10 for chemistry content and 8.5/10 for student engagement. The odds were out of his favor to get real stimulation in a group devoid of geochemical foundations.

To the lay person, this seminar was all about how rocks, in their small form, are affected by water in their natural environment.

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Michael Velbel gave a rather unique presentation by giving a geologist’s perspective on chemistry with his presentation, “Rate and Rate-Determining processes in natural weathering of rock forming minerals”. I was pretty interested throughout the presentation, though the dimming of the lights did have a negative effect on my ability to stay awake. But, from what I was able to remember and stay awake for, it really did seem like an engaging presentation. It was also nice during the end of the presentation how he was able to thoroughly answer all the questions that we had for him, and from the end discussion I was able to learn about how geochemistry can play a role not only in our planet, but elsewhere like the moon or even mars.

I was able to learn several other things from throughout this lecture. First of all, how feldspar dissolves its products and precipitates after. Furthermore i learned that the microscopy constrains how reaction should be written, and studying minerals and their reactions with aqueous solutions improves understanding of the many phenomena on earth and elsewhere in the solar system and beyond. He also explained his SEM techniques and what he was looking for throughout his research. I was also able to learn more about the many things he did during his research.

Overall I thought the presentation was interesting given his clear presentation style and the unique topic being discussed. I would describe this presentation to my non-science friend by saying that through observing minerals and their reactions with aqueous solutions, we can gain further understanding that can help us in our explanations of certain phenomena.

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