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.
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.
Rapid Vortex Fluidics: Continuous Flow Synthesis of Amides and Local Anesthetic Lidocaine
作者:Joshua Britton、Justin M. Chalker、Colin L. Raston
DOI:10.1002/chem.201501785
日期:2015.7.20
on multigram scales. Amide synthesis under flow was also extended to a total synthesis of local anesthetic lidocaine, with sequential reactions carried out in two serially linked VFD units. The synthesis could also be executed in a single VFD, in which the tandem reactions involve reagent delivery at different positions along the rapidly rotating tube with in situ solvent replacement, as a molecular
A Novel Dehydrazination Reaction. V. The Formation of Various Amides from Aliphatic and Aromatic Carboxylic Acid Hydrazides in the Presence of Chloral
作者:Tetsuji Kametani、Osamu Umezawa
DOI:10.1248/cpb.14.369
日期:——
In the previous papers the reactions between aromatic, aliphatic and heterocyclic carboxylic acid hydrazides and either chloral or bromal in various alcohols were attempted and respective esters were obtained. In this paper the reactions of aromatic and aliphatic acid hydrazide with chloral in the presence of various amines were examined, leading eventually to reveal the formation of our expected acid amides as are shown in Table I and II. The intermediates in this reaction, 1-benzoyl-2-(2, 2, 2-trichloroethylidene) hydrazine (III : R=C6H5-, X=Cl) was found to form the amides (VI) when heated in amines. This fact indicated that the acid hydrazides converted to their amides through III.
rate constants of the thermal dissociation of 1,1-dimethyl, 1,3-diethyl, 1,3-diisopropyl, 1,1, 3-triethyl, 1, 3-dihexyl, 1,3-dibenzyl, 1, 1-diethyl-3-isopropyl and 1,3-di-t-butyl ureas in n-butyric,n-caproic,n-capric, phenylacetic and benzoicacids were deter mined. The effects of substituents and those of solvents on the reaction rate were discussed. The transition state of the dissociation containing