T. Back, R. J. Bethell, M. Parvez
Oct 13, 1998
Citations
0
Influential Citations
41
Citations
Journal
Journal of Organic Chemistry
Abstract
1-Phenylseleno-2-(p-toluenesulfonyl)ethyne (4) was produced nearly quantitatively from p-(toluenesulfonyl)ethyne and benzeneselenenyl chloride. It underwent stereo- and regioselective syn-additions of organocopper reagents RCu(CN)Li to the β-position of the sulfone moiety to afford adducts 5. Further reaction of the products with reagents RCu(SePh)Li resulted in substitution of the phenylseleno group with retention of configuration. Control of E,Z-stereochemistry in the product β,β-disubstituted vinyl sulfones is therefore achieved by the order of addition of the reagents. Selenoxide syn-elimination of adducts 5 afforded the corresponding allenic sulfones. The additions of amines and alkoxides to 4 produced the corresponding anti-Michael regioisomers (where attack occurred α to the sulfone group) as the major or sole products. The additions were highly stereoselective, proceeding by anti-addition in the anti-Michael series and by syn-addition in the corresponding Michael regioisomers. The reactions of 4 w...