[4+1] Cyclizations to Enantiopure Multifunctional Cyclopentanes from d-Glucose Using Formyl Dianion Synthons

Abstract

The [4+1] cyclizations of a sugar-based epoxytosylate with various C1 dianion equivalents provides highly functionalized homochiral cyclopentanes. For these, a follow-up chemistry was developed to provide various cyclopentane building blocks as starting points for natural product syntheses. The [4+1] domino protocol relies on a 1,4-Brook rearrangement, which is essential for the generation of the second carbanion.