Development of Tandem Reaction for Synthesis of Highly Functionalized Carbocycles

Abstract

The Suzuki-Miyaura cross-coupling reaction is a common strategy for the formation of a new carbon-carbon bond in organic synthesis. However, intramolecular coupling of allylboron ester and aryl electrophiles has never been reported. Herein, Pd-catalyzed intramolecular cross-coupling of allylboronic pinacol ester and vinyl or aryl bromides is presented. Pt-catalyzed 1,2-diboration of 1,3-dienes give α-chiral bis-allylboronic esters, which can undergo diastereoselective additions to carbonyl electrophiles tethered to vinyl or aryl halides to generate a new allylboronic ester moiety. Under Suzuki coupling conditions, the allylboronic esters moiety and the vinyl bromides in the allylation products can cross-couple in an intramolecular fashion to afford highly substituted four-, five-, and six-membered rings with excellent yields and moderate diastereoselectivity.