Enantioselective friedel-crafts alkylations with benzoylhydrazones promoted by a simple strained silacycle reagent

J Am Chem Soc. 2005 Mar 9;127(9):2858-9. doi: 10.1021/ja042522a.

Abstract

The enantioselective Friedel-Crafts reaction of electron-rich arenes and heteroarenes with the benzoylhydrazone of isopropyl glyoxylate mediated by a simple chiral silane Lewis acid is described. The reactions are highly practical, as demonstrated by a larger scale (5 g of the hydrazone) reaction in which the recovery of the pseudoephedrine in 99% yield was achieved. A simple model is advanced to explain the observed enantioselectivity.