Developments of Asymmetric Synthesis Mediated by Chiral Sulfur Reagents |
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Authors: | Virginie Blot Jean-François Brièr Marion Davoust Stéphanie Minière Vincent Reboul Patrick Metzner |
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Institution: | Laboratoire de Chimie Moléculaire et Thio-organique (UMR CNRS 6507), ENSICAEN , Caen, France |
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Abstract: | Abstract Our work on the thio-Claisen rearrangement mediated by an adjacent sulfinyl group is reviewed. The substrates could easily be prepared on a large scale from diacetone-D-glucose. The rearrangement was effected with a diastereoselectivity of 95:5, in favor of the (S,S) or the (R,R) isomer. An approach to natural bis(lactones) was investigated, using a halolactonization reaction and a second 3,3] sigmatropic shift, again mediated by the sulfinyl group. The second part deals with the catalytic enantioselective benzylidenation of aldehydes, mediated by chiral sulfur ylides. We have introduced simple C 2 symmetric thiolanes for that purpose. The procedure is very practical and enantiomeric excesses up to 96% have been reported for the model of stilbene oxide. A series of ferrocenyl sulfides with planar chirality has also been investigated, leading to unexpected diastereoselectivities and enantiomeric excesses up to 94%. |
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Keywords: | Chiral sulfur ylides epoxides ferrocenes sulfoxides thio-Claisen rearrangement |
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