Asymmetric synthesis of β-lactams. I. The reaction of dimethylketene silyl acetal with (S)-alkylidene(1-arylethyl)amines promoted by titanium tetrachloride

Asymmetric synthesis of β-lactams by means of the reaction of dimethylketene silyl acetal with (S)-alkylidene(1-arylethyl)amines in the presence of titanium tetrachloride was studied. The extent of the asymmetric induction was in the range of 44–78% (diastereomeric purity 72–89%) and the (S)-configuration was turned to be preferentially induced at the ⁴C position of the resulting β-lactams.