Construction of Benzopolycycles via Pd-Catalyzed Intermolecular Cyclization of 2,7-Alkadiynylic Carbonates with Terminal Propargyl Tertiary Alcohols

Abstract

A palladium-catalyzed highly regioselective and chemoselective intermolecular cyclization of 2,7-alkadiynylic carbonates with terminal propargyl tertiary alcohols to construct benzopolycycles containing furan and pyrrole moieties has been developed with a very broad scope. Polycycles containing spirane structures or dispirane structures could be also smoothly synthesized in moderate to good yields. The reaction enjoys excellent regioselectivity.

Lewis-Acid-Catalyzed Tandem Cyclization by Ring Expansion of Tertiary Cycloalkanols with Propargyl Alcohols

“…On the basis of the aforementioned results and the reported literature, a possible reaction pathway is depicted in Scheme . The transformation is initiated by the Lewis-acid-catalyzed dehydration of tertiary cycloalkanols 2 to form species 5 .…”