Facile Approach to Optically Active α-Alkylidene-β-amino Esters by Thermal Overman Rearrangement
作者:Sung Il Lee、Soon Young Moon、Geum-Sook Hwang、Do Hyun Ryu
DOI:10.1021/ol1011746
日期:2010.7.16
A convenient synthetic method for enantioenriched (E)-α-alkylidene-β-amino esters has been developed through thermal Overman rearrangement. Readily accessible (Z)-β-branched Morita−Baylis−Hillman esters serve as chiral pool precursors. Thermalrearrangement proceeded through a concerted pseudopericyclic transition state to produce (E)-stereoselective products. We expanded the synthetic utilities of
An Ester Enolate–Claisen Rearrangement Route to Substituted 4-Alkylideneprolines. Studies toward a Definitive Structural Revision of Lucentamycin A
作者:Sujeewa Ranatunga、Jinsoo S. Kim、Ujjwal Pal、Juan R. Del Valle
DOI:10.1021/jo201727g
日期:2011.11.4
substituted α-allylglycine products with good to excellent diastereoselectivities. Resolution of dipeptide diastereomers and cyclization to form the pyrrolidine rings provide rapid access to stereopure prolyl dipeptides. We have applied this strategy to the synthesis of four Emp-containing isomers of lucentamycin A in pursuit of a definitive stereochemical revision of the naturalproduct. Our studies indicate