Asymmetric synthesis chemistry

See e.g. (a) W. Cahhuthehs, Cycloaddition Reactions in Organic Synthesis, Tetrahedron Organic Chemistry Series Vol. 8 Pergamon Press Elmsford, NY 1990 (b) I. OjiMA, Catalytic Asymmetric Synthesis, VCH Publishers. Inc. New York. 1993 ... 

Asymmetric synthesis is a stimulating academic challenge, but since it has become clear that most chiral drugs can be administered safely only in the enantiomerically pure form, the industrial need for asymmetric methods has made research in asymmetric synthesis absolutely necessary [5]. This has driven a renaissance in the discipline of organic chemistry, because all of the old-established reactions need to be reinvestigated for their application in asymmetric synthesis [6]. This has also applied... 

For his work on chirally catalyzed oxidation reactions, representing a major contribution to the development of catalytic asymmetric synthesis, K. B. Sharpless was awarded the Nobel Prize for chemistry in 2001. ... 

A different approach to making chiral drugs is asymmetric synthesis. An optically inactive precursor is converted to the drug by a reaction that uses a special catalyst, usually an enzyme (Chapter 11). If all goes well, the product is a single enantiomer with the desired physiological effect In 2001, William S. Knowles, Ryogi Noyori, and K. Barry Sharpless won the Nobel Prize in chemistry for work in this area. 

Throughout each chapter, clear structures, schemes, and figures accompany the text. Mechanism, reactivity, selectivity, and stereochemistry are especially addressed. Special emphasis is also placed on introducing both the logic of total synthesis and the rationale for the invention and use of important synthetic methods. In particular, we amplify the most important developments in asymmetric synthesis, catalysis, cyclization reactions, and organometallic chemistry. 

The chemistry of aziridine-2-carboxylates and phosphonates has been discussed in part in several reviews covering the literature through 1999 [1-3], This chapter is intended to give an overview of asymmetric syntheses using chiral nonracemic aziridine-2-carboxylates and -phosphonates with particular emphasis on their applications as chiral building blocks in asymmetric synthesis since 2000. Some overlap with earlier reviews is necessary for the sake of continuity. 

Hodgson et al. showed that a series of bis- and tris-homoallylic terminal epoxides underwent intramolecular cydopropanation to give a range of bicydic alcohols. A short asymmetric synthesis of sabina ketone based on this chemistry was demonstrated (Scheme 5.20). A practical advantage with this process is that the volatile epoxides can be replaced with readily available chlorohydrins, an extra... 

In 20 years of usage, a,/J-unsaturated Fischer carbene complexes demonstrated their multitalented versatility in organic synthesis, yet new reaction types are still being discovered every year. In view of their facile preparation and multifold reactivity, their versatile chemistry will undoubtedly be further developed and applied in years to come. The application of chirally modified Fischer carbene complexes in asymmetric synthesis has only begun, and it will probably be an important area of research in the near future. 

Diastereoselective and enantioselective [3C+2S] carbocyclisations have been recently developed by Barluenga et al. by the reaction of tungsten alkenylcarbene complexes and enamines derived from chiral amines. Interestingly, the regio-chemistry of the final products is different for enamines derived from aldehydes and those derived from ketones. The use of chiral non-racemic enamines allows the asymmetric synthesis of substituted cyclopentenone derivatives [77] (Scheme 30). 

Topochemical [24-2] photoreactions of diolehn crystals has been reviewed. The reactions clearly depart from typical solution chemistry crystal-lattice control offers a unique synthetic route into photodegradable polymers, highly strained [24-2] paracyclophanes, stereoregular polymers, and absolute asymmetric synthesis. However, achieving the desired type of crystal... 

White, J.D., Hrnciar, R, Stappendeck, F. (1997) Asymmetric Synthesis of (-F)-Morphine. The Phenanthrene Route Revisited. Journal of Organic Chemistry, 62, 5250-5251. 

Ojima, 1., Habus, 1., Zhao, M. (1991) Efficient and Practical Asymmetric Synthesis ofthe Taxol C-13 Side Chain, N-Benzoyl-(2R,3S)-3-phenylisoserine, and its Analogues via Chiral 3-Hydroxy-4-aryl-b-lactams Through Chiral Ester Enolate-Imine Cyclocondensation. Journal of Organic Chemistry, 56, 1681-1683. 

This chapter, however, does not deal with above-mentioned reactions of sulfoxides. Rather it is limited to asymmetric synthesis using a-sulfinyl carbanions and -unsaturated sulfoxides, specifically in which the stereogenic sulfoxide sulfur atom is enantiomerically pure. Therefore reactions of racemic sulfoxides are for the most part excluded from this review. For more general discussions, the reader is referred to other chapters in this volume and to other reviews on the chemistry of sulfoxides. Especially useful are the reviews by Johnson and Sharp and by Mislow in the late 1960s and by Oae and by Nudelman as well as a book by Block . A review by Cinquini, Cozzi and Montanari" through mid-1983 summarizes the chemistry and stereochemistry of optically active sulfoxides. This chapter emphasizes results reported from 1984 through mid-1986. 

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