endo-Selective allylation at the benzylic centre of a Cr(CO)3 complexed aromatic ring

Abstract

In the presence of TiCl₄, allyllithium adds to tricarbonylchromium complexes of 2-arylidene-1-tetralone and 2-arylideneindan-1-one (1a–c) to afford endo-1,2-adducts (2a–c) exclusively. Subsequent oxy-Cope rearrangement delivers the allyl group stereospecifically along the endo-face to the sterically hindered benzylic position of the metal-complexed ring.