Rhodium(II)-catalyzed stereocontrolled synthesis of 2-tetrasubstituted saturated heterocycles from 1-sulfonyl-1,2,3-triazoles.

Rhodium(II) acetate catalyzes the denitrogenative transformation of 4-substituted 1-sulfonyl-1,2,3-triazoles with pendent allyl and propargyl ethers and thioethers to onium ylides that undergo [2,3]-sigmatropic rearrangement to give 2-tetrasubstituted heterocycles with high yield and diastereoselectivity.