Reversed Stereochemical Course of the Michael Addition of Cyclohexanone to β‐Nitrostyrenes by Using 1‐(Trimethylsiloxy)cyclohexene/Dichloro(diisopropoxy)titanium. Preliminary Communication

Abstract Induced by a stoichiometric excess of dichloro(diisopropoxy)titanium, 1‐(trimethylsiloxy)cyclohexene and p ‐substituted β‐nitrostyrenes (Y = H,CH 3 ,CH 3 O,CN) combine in CH 2 Cl 2 solution at −90° preferentially with relative topicity ul – opposite to the corresponding reaction of enolates or enamines. The primary products are the bicyclic nitronates 3–5 which can be separated, and which are cleaved by KF in MeOH to give the …