Directed C–C bond cleavage of a cyclopropane intermediate generated from<i>N</i>-tosylhydrazones and stable enaminones: expedient synthesis of functionalized 1,4-ketoaldehydes
-quaternary centers via regioseletive C-C bond activation has been described. Through cyclopropanation of bench-stable enaminones with in situ generated diazo reagents from N-tosylhydrazones, followed by selective C-C bond cleavage of the cyclopropane ring affords the 1, 4-ketoaldehyde derivatives in good to excellent yields. This method works with broad substrate scope and high regioseletivity.
A New Protocol for the In Situ Generation of Aromatic, Heteroaromatic, and Unsaturated Diazo Compounds and Its Application in Catalytic and Asymmetric Epoxidation of Carbonyl Compounds. Extensive Studies To Map Out Scope and Limitations, and Rationalization of Diastereo- and Enantioselectivities
作者:Varinder K. Aggarwal、Emma Alonso、Imhyuck Bae、George Hynd、Kevin M. Lydon、Matthew J. Palmer、Mamta Patel、Marina Porcelloni、Jeffery Richardson、Rachel A. Stenson、John R. Studley、Jean-Luc Vasse、Caroline L. Winn
DOI:10.1021/ja034606+
日期:2003.9.1
a general process for the in situ generation of diazo compounds from tosylhydrazone sodium salts has been established and applied in sulfur-ylide mediated epoxidation reactions. The chiral, camphor-derived, [2.2.1] bicyclic sulfide 7 was employed (at 5-20 mol % loading) to render the above processes asymmetric with a range of carbonyl compounds and tosylhydrazone sodium salts. Benzaldehyde tosylhydrazone
Transition Metal, Azide, and Oxidant-Free Homo- and Heterocoupling of Ambiphilic Tosylhydrazones to the Regioselective Triazoles and Pyrazoles
作者:Subhankar Panda、Pradip Maity、Debasis Manna
DOI:10.1021/acs.orglett.7b00313
日期:2017.4.7
cyclization reaction of two identical or different tosylhydrazones has been developed to access various 4,5-disubstituted-2H-triazoles under transition metal, azide, and oxidant-free conditions. A mechanistic rationalization study led to the identification of several electronically diverse unsaturated systems for regioselective synthesis of 1- and 2-substituted 1,2,3-triazoles and pyrazoles.
Catalytic Cyclopropanation of Alkenes Using Diazo Compounds Generated in Situ. A Novel Route to 2-Arylcyclopropylamines
作者:Varinder K. Aggarwal、Javier de Vicente、Roger V. Bonnert
DOI:10.1021/ol0164177
日期:2001.8.1
[reaction: see text]. A user-friendly, one-pot process for catalyticcyclopropanation of alkenes from tosylhydrazones is described. The cyclopropanation of N-vinylphthalimide provides a new route to 2-arylcyclopropylamines, and this is exemplified in the efficient synthesis of the HIV-1 reverse transcriptase inhibitor 6.
Diastereoselective Synthesis of Cyclopropane Amino Acids Using Diazo Compounds Generated in Situ
作者:Luke A. Adams、Varinder K. Aggarwal、Roger V. Bonnert、Bettina Bressel、Russell J. Cox、Jon Shepherd、Javier de Vicente、Magnus Walter、William G. Whittingham、Caroline L. Winn
DOI:10.1021/jo035060c
日期:2003.11.1
E selectivity, while reactions in the presence of meso-tetraphenylporphyrin iron chloride gave predominantly the corresponding Z isomers. The synthetic utility of this process was demonstrated in the synthesis of (+/-)-(Z)-2,3-methanophenylalanine [(+/-)-(Z)-1], the anti-Parkinson (+/-)-(E)-2,3-methano-m-tyrosine [(+/-)-(E)-2], and the natural product (+/-)-coronamic acid [(+/-)-3].