Fusion of Photochromic Reaction and Synthetic Reaction: Photoassisted Cyclization to Highly Strained Chiral Azobenzenophanes

Abstract

A method for synthesizing highly strained cyclic structures by combining photochromic and synthetic reactions is described. Tightly linked azobenzene–binaphthyl dyads (<i>R</i>)-<b>4</b> and (<i>R</i>)-<b>6</b> could not be obtained by conventional cyclization, but continuous application of photoirradiation, which induced (<i>E</i>)→(<i>Z</i>) isomerization of the azobenzene moiety, allowed the cyclization reaction to proceed, affording the desired chiral azobenzenophanes