Asymmetric Synthesis of anti- and syn-2,3-Diamino Esters Using Sulfinimines. Water and Concentration Effects
摘要:
In the absence of water, an excess of the lithium enolate of N-(diphenylmethylene)glycine ethyl ester (4) adds to sulfinimines to give syn-2,3-diamino esters 6, and in the presence of water, this enolate gives the anti-2,3-diamino esters 5. These unusual results are interpreted in terms of those factors that inhibit the retro-Mannich fragmentation in the diamino esters.
Asymmetric Synthesis of syn-(2R,3S)- and anti-(2S,3S)-Ethyl Diamino-3-phenylpropanoates from N-(Benzylidene)-p-toluenesulfinamide and Glycine Enolates
摘要:
Addition of differentially N-protected glycine enolates to enantiopure sulfinimines affords syn- and anti-alpha,beta-diamino esters with high diastereoselectivities and good yields.