Enantioselective friedel-crafts alkylations with benzoylhydrazones promoted by a simple strained silacycle reagent.
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.
Shirakawa
Seiji
S
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Berger
Richard
R
Leighton
James L
JL