A mild method of reduction of the N-0 bond of substituted N-hydroxy-2-azetidinones was required to complete a hydroxamic acid mediated synthesis of substituted (I-lactams. Of the several reduction methods studied, most either failed to reduce the NO bond, cleaved the 2- azetidinone ring, or were inefficient and inconvenient. However, buffered titanium trichloride cleanly reduced the N-0 bond of the N-hydroxy-2-azetidinones under conditions ...