A Stereoselective and Regioselective Synthesis of trans,trans-Configured 1,2,3-Trisubstituted Indanes: Cycloaddition of Alkenes with Iodonium Ylides of β-Disulfones

The reaction of phenyliodonium-bis(sulfonyl) methylides α-γ with alkenes 1 affords the multiply trisubstituted indanes 2 in moderate to good yields, through an unusual cycloaddition. The present stereoselective and regioselective cycloaddition provides a convenient preparative route to trans,trans-configured 1,2,3-trisubstituted indanes, in which the benzene ring derives from the arenesulfonyl functionality of the bis(sulfonyl)iodonium ylide. The mechanistically puzzling structural feature is the fact (X-ray structure) that the para-methyl substituent of the original p-toluenesulfonyl group in the iodonium ylide is located in the C-6 position of the resulting indane benzene ring, that is, a meta relationship with respect to the original methylide carbon atom.