H. Ishibashi et al., ASYMMETRIC INDUCTION IN RADICAL CYCLIZATION LEADING TO BETA-LACTAMS -FORMAL SYNTHESIS OF (-PS-5()), Synlett, (6), 1994, pp. 445-446
Tributyltin hydride-mediated radical cyclization of 2,2-bis(phenylthio
)ethenyl]-alpha-bromoalkanamides bearing (S)-1-phenylethyl group on th
e nitrogen atom gave (4S)-4-bis(phenylthio)-methyl-2-azetidinones as m
ajor products. The method was applied to the synthesis of a chiral pre
cursor of carbapenem antibiotic (+)-PS-5.