Enantioselective cyanation/Brook rearrangement/C-acylation reactions of acylsilanes catalyzed by chiral metal alkoxides.
New catalytic enantioselective cyanation/1,2-Brook rearrangement/C-acylation reactions of acylsilanes (4) with cyanoformate esters (7) are described. The products of the reaction are fully substituted malonic acid derivatives (8). Catalysts for this transformation were discovered via a directed candidate screen of 96 metal-ligand complexes. Optimization of a (salen)aluminum complex revealed significant remote electronic effects and concentration effects. The scope of the reaction was investigated by using a number of aryl acylsilanes and cyanoformate esters. Chemoselective reduction of the reaction products (8) afforded new enantioenriched alpha-hydroxy-alpha-aryl-beta-amino acid derivatives (32-34) and beta-lactams (35 and 36). This reaction provides a simple method for the construction of new nitrogen-containing enantioenriched chiral building blocks.
Nicewicz
David A
DA
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Yates
Christopher M
CM
Johnson
Jeffrey S
JS
D000215:Acylation; D002384:Catalysis; D003485:Cyanates / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism
D003485:Cyanates; D008670:Metals; D010087:Oxides; D012821:Silanes