Direct Acyl Substitution of Carboxylic Acids: A Chemoselective O- to N-Acyl Migration in the Traceless Staudinger Ligation
作者:Andrew D. Kosal、Erin E. Wilson、Brandon L. Ashfeld
DOI:10.1002/chem.201201773
日期:2012.11.5
chlorophosphite‐modified, Staudinger‐like acylation of azides involving a highly chemoselective, direct nucleophilic acyl substitution of carboxylicacids is described. The reaction provides the corresponding amides with analytical purity in 32–97 % yield after a simple aqueous workup without the need for a pre‐activation step. The use of chlorophosphites as dual carboxylic acid–azide activating agents
Practical copper(i)-catalysed amidation of aldehydes
作者:Joyce Wei Wei Chang、Thi My Uyen Ton、Stefani Tania、Paul C. Taylor、Philip Wai Hong Chan
DOI:10.1039/b918588g
日期:——
The direct synthesis of amides by insertion into the C-H bond of aldehydes is shown to be a practical procedure through application of cheap, readily available catalysts generated in situ from copper(i) halides and pyridine.
from aldehydes by an iron-catalyzed nitreneinsertionreaction has been developed. Both aryl and aliphatic aldehydes can directly afford the corresponding amides with an iron(II)-terpyridine (tpy) complex formed in situ as catalyst, and PhI=NTs as nitrogen source under mild reaction conditions. An ESI-MS study revealed the formation of [Fe(tpy) 2 (NTs)] 2+ as a reaction intermediate.
Transacylation of N-acylsulfonamides, which replaces the N-acyl group with a new one, is a challenging and underdeveloped fundamental transformation. Herein, a general method for transacylation of N-acylsulfonamides is presented. The transformation is enabled by coincident catalytic reactivities of FeCl3 for nonhydrolytic deacylation of N-acylsulfonamides and subsequent acylation of the resultant sulfonamides