Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C–H Activation
摘要:
alpha,beta-Unsaturated - oxime pivalates are proposed to undergo reversible C(sp(2))-H insertion with cationic Rh (III) complexes to furnish five-membered metallacycles. In the presence of 1,1-disubstituted olefins, these species participate in irreversible migratory insertion to give, after reductive elimination, 2,3-dihydropyridine products in good yields. Catalytic hydrogenation can then be used to. convert these molecules into piperidines, which are important structural components of numerous pharmaceuticals.
Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C–H Activation
摘要:
alpha,beta-Unsaturated - oxime pivalates are proposed to undergo reversible C(sp(2))-H insertion with cationic Rh (III) complexes to furnish five-membered metallacycles. In the presence of 1,1-disubstituted olefins, these species participate in irreversible migratory insertion to give, after reductive elimination, 2,3-dihydropyridine products in good yields. Catalytic hydrogenation can then be used to. convert these molecules into piperidines, which are important structural components of numerous pharmaceuticals.
作者:Stephen F. Martin、David A. Kummer、Jehrod B. Brenneman
DOI:10.1055/s-2004-829095
日期:——
A new method for preparing α-branched enonesfrom carboxylic acid derivatives is reported. The procedure commenced by the reaction of N,O-dimethylamides with a masked acyl anionequivalent, followed by the addition of (trimethylsilyl-methyl)cerium dichloride to give intermediates that undergo Lewis acid mediated olefination to produce enol ethers that are then hydrolyzed to afford simple α-branched