Herein, direct N,N-dialkylation of acylhydrazides using alcohols is reported. This catalytic protocol provides one-pot synthesis of both symmetrical and unsymmetrical N,N-disubstituted acylhydrazides using an assortment of primary and secondary alcohols with remarkable selectivity and excellent yields. Interestingly, the use of diols resulted in intermolecular cyclization of acylhydrazides, and such
作者:W. Russell Bowman、Peter T. Stephenson、Nicholas K. Terrett、Adrian R. Young
DOI:10.1016/0040-4020(95)00412-2
日期:1995.7
Radical cyclisation of sp3 carbon-centred radicals onto imines and hydrazones provides a new method for the synthesis of 5- and 6-membered ring nitrogen heterocycles. Cyclisation onto the electrophilic carbon of the C=N group and 5-exo stereoelectronic selectivity are the dominating mechanistic parameters. The C-centred radical intermediates were generated from benzeneselenyl precursors using Bu3SnH
A practical and transition-metal-freeoxidative cyclization of acylhydrazones into 1,3,4-oxadiazoles has been developed by employing stoichiometric molecular iodine in the presence of potassium carbonate. The conditions of this cyclization reaction also work well with crude acylhydrazone substrates obtained from the condensation of aldehydes and hydrazides. A series of symmetrical and asymmetrical
Development of General Catalytic Allylation of Acylhydrazones with Pinacolyl Allylboronate Using an Indium(I) Catalyst
作者:Uwe Schneider、I-Hon Chen、Shū Kobayashi
DOI:10.1021/ol702756k
日期:2008.3.1
Catalytic allylation of various acylhydrazones using a group 13 metal reagent (boron) in combination with a group 13 metal catalyst in its low-oxidation state (indium) has been developed. This operationally simple carbon-carbon bond-forming reaction displays remarkable substrate scope and functional group tolerance.
A simple and efficient method for the synthesis of α-(N′-acylhydrazino)-substituted phosphonates has been developed using the hydrophosphonylation of benzoylhydrazones with triethyl phosphite in the presence of iodine as a catalyst at room temperature. The products are formed in excellent yields (89-95%) within two to three hours.