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Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag February 7, 2014

Stereoselective Di-pi-Methane Rearrangement of a BINOL-Substituted Dibenzobarrelene Derivative

Heiko Ihmels and Jia Luo

Abstract

Two dibenzobarrelene derivatives were synthesized that are covalently linked to a (S)-BINOL unit through an oxymethylene (1b) or ethylenedioxymethylene (1c) unit, and their photoreactivity was examined. Irradiation of 1b in acetone resulted in a di-π-methane rearrangement to give diastereoselectively one dibenzosemibullvalene isomer. Experimental and theoretical data point to a directing effect of the BINOL auxiliary based on steric repulsion. The derivative 1c with a longer linker between the BINOL unit and the dibenzobarrelene is photoinert, presumably because of fast competing relaxation processes in the excited state.

Received: 2013-10-4
Accepted: 2013-11-26
Published Online: 2014-2-7
Published in Print: 2014-3-28

©2014 Walter de Gruyter Berlin/Boston