Diastereoselective sulfur ylide rearrangements from gold catalyzed oxidation of ynamides

The [2,3]-sigmatropic rearrangement of sulfonium ylides bearing substituted allyl groups creates two contiguous stereocentres. Low diastereoselectivity is typically observed from commonly used alpha-diazocarboxylic ester precursors. High diastereoselectivity was previously revealed in a gold-catalyzed multicomponent route into allyl sulfonium ylides by reaction of ynamide, oxidant and allyl sulfides. The effect of substrate modifications on the diastereoselectivity have been studied, with N-phenyl methanesulfonamide derived ynamides proving the most effective. This report includes an enhanced experimental procedure, and a demonstration that the gold-catalyzed process remains highly effective at -78 degrees C. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates high diastereoselectivity in the synthesis of allyl sulfonium ylides through a gold-catalyzed multicomponent route. Modifying the substrate structure, N-phenyl methanesulfonamide derived ynamides are found to be the most effective precursors.