Stereoselective Mannich-type reaction of chlorotitanium α-phenylseleno esters enolates with aromatic aldimines

The stereoselective Mannich-type reaction of α-phenylseleno chlorotitanium enolates with aromatic aldimines is described. The corresponding α-phenylseleno-β-amino esters were obtained in good yields and with moderate to good diastereoselectivity. A rationale for the predominant syn selectivity based on a chelated cyclic transition state is suggested. The obtained compounds are useful synthetic tools and direct precursors of new α-phenylseleno-β-lactams.