PPL-catalysed hydrolysis of 3,4-disubstituted β-lactams: Effect of chain length and stereochemistry on the enantioselectivity
摘要:
3,4-Disubstituted beta-lactam acetates 1a-15a have been subjected to PPL-catalysed hydrolysis. The stereochemical course of hydrolysis has been shown to depend upon the C3-C4 relative stereochemistry and the length of the chain bearing acetate functionality. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
A novel, selective palladium-catalysed carbenoid C(aryl)-H insertion of [small alpha]-diazo-[small alpha]-(methoxycarbonyl)acetanilides leading to oxindoles is described.
Reaction of arylacetylenes with C,N-diarylnitrones using a catalyst system of CuI-dppe (dppe = 1,2-bis(diphenylphosphino)ethane) in the presence of potassium carbonate in DMF predominantly affords the corresponding 1,2,4-triaryl-1-aza- 1-buten-3-ynes in good yields. In contrast, the catalytic reaction using CuI in the presence of an excess amount of pyridine as the ligand gives 1,3,4-triaryl-2-azetidinones as the major products. The reaction with aliphatic terminal alkynes in place of arylacetylenes produces the latter products irrespective of the catalyst system used. Asymmetric induction is also observed in the reaction of phenylacetylene with alpha,N-diphenylnitrone to give 1,2,4-triphenyl-2-azetidinone in the presence of chiral bisoxazoline-type ligands.
Casadei, Maria Antonietta; Moracci, Franco Micheletti; Inesi, Achille, Journal of the Chemical Society. Perkin transactions II, 1986, p. 419 - 424
作者:Casadei, Maria Antonietta、Moracci, Franco Micheletti、Inesi, Achille
DOI:——
日期:——
PPL-catalysed hydrolysis of 3,4-disubstituted β-lactams: Effect of chain length and stereochemistry on the enantioselectivity
3,4-Disubstituted beta-lactam acetates 1a-15a have been subjected to PPL-catalysed hydrolysis. The stereochemical course of hydrolysis has been shown to depend upon the C3-C4 relative stereochemistry and the length of the chain bearing acetate functionality. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.