Metal-free, hydroacylation of CC and NN bonds via aerobic C–H activation of aldehydes, and reaction of the products thereof
作者:Vijay Chudasama、Ahmed R. Akhbar、Karim A. Bahou、Richard J. Fitzmaurice、Stephen Caddick
DOI:10.1039/c3ob41632a
日期:——
In this report, a thorough evaluation of the use of aerobically initiated, metal-free hydroacylation of various CC and NN acceptor molecules with a wide range of aldehydes is presented. The aerobic-activation conditions that have been developed are in sharp contrast to previous conditions for hydroacylation, which tend to use transition metals, peroxides that require thermal or photochemical degradation, or N-heterocyclic carbenes. The mildness of the conditions enables a number of reactions involving sensitive reaction partners and, perhaps most significantly, allows for α-functionalised chiral aldehydes to undergo radical-based hydroacylation with complete retention of optical purity. We also demonstrate how the resulting hydroacylation products can be transformed into other useful intermediates, such as γ-keto-sulfonamides, sultams, sultones, cyclic N-sulfonyl imines and amides.
One-Pot Amide Bond Formation from Aldehydes and Amines via a Photoorganocatalytic Activation of Aldehydes
作者:Giorgos N. Papadopoulos、Christoforos G. Kokotos
DOI:10.1021/acs.joc.6b00488
日期:2016.8.19
environmentally friendly synthesis of amides from aldehydes and amines is described. Initially, a photoorganocatalytic reaction of aldehydes with di-isopropyl azodicarboxylate leads to an intermediate carbonyl imide, which can react with a variety of amines to afford the desired amides. The initial visible light-mediated activation of a variety of monosubstituted or disubstituted aldehydes is usually fast,
Enabling the facile conversion of acyl hydrazides into N-acyl carbamates via metal-free ionic-based rupture of the N–N linkage
作者:André Shamsabadi、Jack Ren、Vijay Chudasama
DOI:10.1039/c7ra04178k
日期:——
the one-pot transformation of readily synthesised/easily accessed acyl hydrazides into N-acyl carbamatesvia an alkylation-elimination reaction sequence. A range of N-acyl carbamates are prepared in consistent yields, including those featuring protectinggroups and having alkyl & aryl N-acyl functionality. The reaction conditions also tolerate a wide variety of sensitive functional groups.
Visible-Light-Mediated Catalytic Hydroacylation of Dialkyl Azodicarboxylates by Graphite Flakes
作者:Giorgos S. Koutoulogenis、Maroula G. Kokotou、Errika Voutyritsa、Dimitris Limnios、Christoforos G. Kokotos
DOI:10.1021/acs.orglett.7b00519
日期:2017.4.7
A nova and efficient Metal-free catalyted hydroacylation of dialkyl azodicarboxylates is reported. Graphite flakes were found to be the most efficient catalyst among other carbon-based materials to prothote this reaction. This unprecedented catalytic activity can be expanded into a wide substrate scope of aliphatic aldehydes bearing various functional groups, leading to the corresponding products in good to excellent yields.
Functionalisation of aldehydes via aerobic hydroacylation of azodicarboxylates ‘on’ water
作者:Vijay Chudasama、Jenna M. Ahern、Dipti V. Dhokia、Richard J. Fitzmaurice、Stephen Caddick
DOI:10.1039/c0cc04520a
日期:——
Herein we report the functionalisation of aldehydesvia hydroacylation of azodicarboxylates. A range of functionalised aldehydes are employed as the limiting reagent including chiral non-racemic aldehydes bearing α-stereocentres which are functionalised giving access to enantiomerically pure products. The resultant hydrazides can be employed as acyl donors in the synthesis of amides.