Stereoselective synthesis of organic

J. Mattay, R. Conrads, and R. Hoffmann in Houben-Weyl Methoden der Organischen Ghemie, Vol. E21c Stereoselective Synthesis of Organic Compounds , G. Helmchen, R. W. Hoffmann, J. Mulller, and E. Schaumann, Eds. Thieme, Stuttgart, 1995, p. 3133. 

Cozzi F. and Molteni V. Stereoselective Synthesis of Dihydropyrans hy Hetero Diels-Alder Reactions in in Seminars in Organic Synthesis 22th Summer Sch A. Corbella 1997 95, Ed. Trombini, Pb. Soc. Chim. Ital. 

Pandey, G., Bagul, T.D., Sahoo, A.K. (1998) [3 -E 2] Cycloaddition of Non stabilized Azomethine Ylides. 7. Stereoselective Synthesis of Epibatidine and Analognes. Journal of Organic Chemistry, 63, 760-768. 

Recent research deals with stereoselective 1,3-dipolar cycloadditions of nitrones for the syntheses of alkaloids and aza heterocycles asymmetric synthesis of biologically active compounds such as glycosidase inhibitors, sugar mimetics, /3-lactams, and amino acids synthesis of peptido-mimetics and peptides chemistry of spirocyclopropane heterocycles synthesis of organic materials for molecular recognition and photochemical applications. 

This manuscript is based on a lecture presented in the "Stereoselective Synthesis of Carbohydrates from Acyclic Precursors" Symposium at the 194th American Chemical Society National Meeting, New Orleans, September 2,1987. This research is also discussed in Roush, W. R., "Strategies and Tactics in Organic Synthesis," Vol. 2. Lindberg, T., ed. Academic Press New York, 1988. 

The pyridoxal-5 -phosphate dependent serine hydroxymethyltransferase (SHMT EC 2.1.2.1) in vivo catalyzes the interconversion of L-serine 158 and glycine 149 by transfer of the /1-carbon of L-serine to tetrahydrofolate (THF) by which the activated formaldehyde is physiologically made available as a C,-pool. The reaction is fully reversible and provides a means for the stereoselective synthesis of 158 in vitro from donor 149 and formaldehyde. Economical yields (88-94%) of L-serine have thus been obtained on a multimolar scale using raw cell extracts of recombinant Klebsiella aerogenes or E. coll in a controlled bioreactor at final product concentrations > 450 gl 1 [461,462], Several SHMTs have been purified and characterized from various organisms including animal tissues [463,464], eucaryotic [465] and procaryotic... 

Ma, L., and Dolphin, D. (1996) Stereoselective synthesis of new chlorophyll a related antioxidants isolated from margin organisms. J. Org. Chem. 61, 2501-2510. 

Pandey, G., Hajra, S., Ghorai, M.K., and Kumar, K.R. (1997) Visible light initiated photosensitized electron transfer cyclizations of aldehydes and ketones to tethered a,p-unsaturated esters stereoselective synthesis of optically pure C-furanosides. Journal of Organic Chemistry, 62, 5966-5973. 

When I was a graduate student in the Department of Chemistry at the University of Pittsburgh, I took organic chemistry courses taught by Professors Craig S. Wilcox and Dennis P. Curran. One of the most amazing topics that I learned about from their lectures was stereoselective synthesis in organic chemistry. 

Thioxanthenes are not only valuable synthetic intermediates [1], they also find considerable interest in pharmaceutical research [2] and as dyes for numerous applications [3]. Only few methods are known for the stereoselective synthesis of S-heterocycles [4], Sequential transformations are a powerful strategy in organic synthesis frequently allowing the synthesis of complex molecules in a single synthetic operation [5]. It was anticipated that 4-silyloxy-l-benzothiopyrylium-salts 1 [6], which represent double-activated 4-thiochromanones, can be used for the stereoselective synthesis of aimulated thiochromanones 3 by reaction with 2-silyloxy-l,3-butadienes 2 [7]. 

Both intermolecular and intramolecular additions of carbon radicals to alkenes and alkynes continue to be a widely investigated method for carbon-carbon bond formation and has been the subject of a number of review articles. In particular, the inter- and intra-molecular additions of vinyl, heteroatomic and metal-centred radicals to alkynes have been reported and also the factors which influence the addition reactions of carbon radicals to unsaturated carbon-carbon bonds. The stereochemical outcome of such additions continues to attract interest. The generation and use of alkoxy radicals in both asymmetric cyclizations and skeletal rearrangements has been reviewed and the use of fi ee radical reactions in the stereoselective synthesis of a-amino acid derivatives has appeared in two reports." The stereochemical features and synthetic potential of the [1,2]-Wittig rearrangement has also been reviewed. In addition, a review of some recent applications of free radical chain reactions in organic and polymer synthesis has appeared. The effect of solvent upon the reactions of neutral fi ee radicals has also recently been reviewed. ... 

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