A new silicon lewis acid for highly enantioselective mannich reactions of aliphatic ketone-derived hydrazones.
The first general method for the highly enantioselective Mannich reaction of aliphatic ketimines is reported. A new, second generation chiral silane Lewis acid has been developed that promotes the reaction between ketone-derived hydrazones and silyl ketene acetals, providing the beta,beta-disubstituted beta-amino esters with good enantioselectivity even for the hydrazone derived from 2-butanone (methyl vs ethyl, 91% ee). Several examples are provided, including a reaction with a substituted (propanoate-derived) silyl ketene acetal.
Notte
Gregory T
GT
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Leighton
James L
JL
D000080:Acetals / Q000737:chemistry; D000596:Amino Acids / Q000138:chemical synthesis*; D004952:Esters / Q000138:chemical synthesis; D005030:Ethylenes / Q000737:chemistry; D006835:Hydrazones / Q000138:chemical synthesis / Q000737:chemistry*; D007097:Imines / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D012821:Silanes / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
D000080:Acetals; D000596:Amino Acids; D004952:Esters; D005030:Ethylenes; D006835:Hydrazones; D007097:Imines; D007659:Ketones; D012821:Silanes; C008223:ketene