Chiral dithiolane sulphoxides: An efficient stereoselective synthesis of (R) and (S)-3-benzoyloxy-2-butanone
摘要:
The effect of the addition of water on the asymmetric oxidation of an acyl dithiane and an acyl dithiolane has been studied. The use of enantiomerically pure dithiolane sulphoxides is demonstrated in a highly selective synthesis of (R)-3-benzoyloxy-2-butanone which depends upon a diastereoselective ketone reduction.
Enantioselective preparation of 2-substituted- 1,3-dithiane 1-oxides using modified sharpless sulphoxidation procedures
作者:Philip C. Bulman Page、Robin D. Wilkes、Emest S. Namwindwa、Michael J. Witty
DOI:10.1016/0040-4020(95)01029-7
日期:1996.2
carried out using modified Sharpless conditions to furnish the corresponding sulphoxides in optically enriched form. Deacylation of 2-acyl-1,3-dithiane 1-oxide derivatives allows the preparation of 2-alkyl-1,3-dithiane 1-oxides and the parent 1,3-dithiane 1-oxide itself in high enantiomeric excesses.
The selective formation of optically active 2-acyl-2-alkyl-1,3-dithiolane 1,1-dioxides from the corresponding 2-acyl-2-alkyl-1,3-dithiolane 1-oxides, by reaction with OsO4 and NMO in acetone, is reported. These compounds underwent stereoselective reactions at the carbonyl group of the acyl group with organometallic reagents. These reactions were completely regioselective, and no attack at either of
Enhanced diastereo and enantioselectivity in the formation of acyldithiolane sulphoxides by the asymmetric oxidation of their enolsilyl ethers
作者:M.Teresa Barros、Alcino J. Leitão、Christopher D. Maycock
DOI:10.1016/s0040-4039(97)01101-5
日期:1997.7
The sulphoxidation of the enol ethers of some acyldithiolanes using the Sharpless epoxidation reagents followed by fluorolysis results in better overall stereoselectivity than direct oxidation of the acyldithiolane thus providing a highly stereoselective route to acyldithiolane sulphoxides. Fluorolysis under acid conditions of non terminal enol ethers results in complete racemisation of the product. (C) 1997 Published by Elsevier Science Ltd.