Alkynyl Halo-Aza-Prins Annulative Couplings

J Org Chem. 2023 Dec 1;88(23):16065-16075. doi: 10.1021/acs.joc.3c01305. Epub 2023 Nov 16.

Abstract

This article is a comprehensive report describing our studies in the field of aza-alkynyl Prins chemistry, comparing and contrasting the different reaction partners and reactivities observed during method development. The synthetic strategies combine an alkynyl aza-Prins coupling with an annulation, enabling the preparation of different nitrogen-containing heterocycles. Different iminium ions are explored as viable electrophiles for an alkynyl Prins cyclization, terminated by capture with a halogen nucleophile to form a vinyl halide. The synthetic utility of this functional handle is exploited through a number of Suzuki cross-couplings, allowing for the preparation of a modest library of compounds. In most cases, the Prins couplings are highly selective for the vinyl halides with E geometry, resulting from anti-addition across the alkyne.