Selective deprotection strategies to N-(α-methylbenzyl)-β-amino esters and derived β-lactams
作者:Stephen G Davies、Osamu Ichihara
DOI:10.1016/s0040-4039(98)01193-9
日期:1998.8
variety of N,N-diprotected β-amino esters, prepared by highly diastereoselective conjugate addition of chirallithium amides, were selectively mono-deprotected under either reductive (hydrogenolysis) or oxidative (DDQ or CAN) conditions. Combined with these deprotection methods, lithium (α-methylbenzyl)(3,4-dimethoxybenzyl) amide 2 can be used as an efficient differentially protected chiral ammonia equivalent
Asymmetric synthesis of β-lactams and pseudopeptides via stereoselective conjugate additions of lithium (α-methylbenzyl)allylamide to α,β-unsaturated iron acyl complexes
作者:Stephen G. Davies、Narciso M. Garrido、Paul A. McGee、John P. Shilvock
DOI:10.1039/a906633k
日期:——
undergoes stereoselective conjugate additions to α,β-unsaturated iron acyl complexes 3a–c to afford β-amino iron acyl adducts 5a–c and 6a–c. These adducts may be deallylated smoothly using palladium(0) catalysis providing the corresponding homochiral secondary amines 7a–c which, upon oxidative decomplexation with bromine or N-bromosuccinimide, undergo direct β-lactam ring formation. The diastereoselectivity