(R)- or (S)-benzyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7a) and (R)- or (S)-1,1-dimethylethyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7b), readily available from serine, react with Wittig reagents to give alkenes 8. Selective deprotection followed by oxidation of the resulting unsaturated amino alcohols 9 provides vinylglycines 5 of defined configuration (> 95% ee) and double-bond geometry. D-Vinylglycines are obtained from L-serine, and conversely, D-serine gives beta,gamma-unsaturated amino acids with the L configuration. The double-bond geometry is controlled by the nature of the phosphorous ylide employed. The scope and limitations of this new methodology for the preparation of chiral vinylglycines is examined.
Synthesis of the C10–C24 fragment of (+)-cannabisativine
作者:Srivari Chandrasekhar、Bhoopendra Tiwari
DOI:10.1016/j.tetasy.2009.07.037
日期:2009.8
The Stereoselective synthesis of the C10-C24 fragment of(+)-cannabisativine has been achieved. The key steps involved in this strategy are the Sharpless asymmetric dihydroxylation, the diastereoselective allylation of an imine, and the ring closing metathesis (RCM). (C) 2009 Elsevier Ltd. All rights reserved.
BEAULIEU, PIERRE L.;DUCEPPE, JEAN-SIMON;JOHNSON, CAROLYNE, J. ORG. CHEM., 56,(1991) N3, C. 4196-4204
作者:BEAULIEU, PIERRE L.、DUCEPPE, JEAN-SIMON、JOHNSON, CAROLYNE
DOI:——
日期:——
Synthesis of chiral vinylglycines
作者:Pierre L. Beaulieu、Jean Simon Duceppe、Carolyne Johnson
DOI:10.1021/jo00013a023
日期:1991.6
(R)- or (S)-benzyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7a) and (R)- or (S)-1,1-dimethylethyl 4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (7b), readily available from serine, react with Wittig reagents to give alkenes 8. Selective deprotection followed by oxidation of the resulting unsaturated amino alcohols 9 provides vinylglycines 5 of defined configuration (> 95% ee) and double-bond geometry. D-Vinylglycines are obtained from L-serine, and conversely, D-serine gives beta,gamma-unsaturated amino acids with the L configuration. The double-bond geometry is controlled by the nature of the phosphorous ylide employed. The scope and limitations of this new methodology for the preparation of chiral vinylglycines is examined.