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N ‐Acyl‐ N ‐tosylhydrazine as a Synthon To Construct Tetrasubstituted Carbon Centers Possessing a Nitrogen Group
Author(s) -
Namba Kosuke,
Shobo Yoshihiro,
Fujimoto Kazuki,
Shoji Isamu,
Yoshida Masahiro,
Tanino Keiji
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402650
Subject(s) - synthon , chemistry , intramolecular force , ring (chemistry) , nucleophile , amine gas treating , acyl group , stereochemistry , intramolecular reaction , medicinal chemistry , quaternary carbon , carbon fibers , group (periodic table) , catalysis , organic chemistry , enantioselective synthesis , materials science , composite number , composite material
Abstract New halohydrazidation and hydrazidopalladation reactions were developed that use the synthon N ‐acyl‐ N ‐tosylhydrazine. The intramolecular bromohydrazidation reactions of β,γ‐unsaturated N ‐acyl‐ N ‐tosylhydrazines readily afforded pyrazolidinone ring systems that contained a tetrasubstituted carbon center, and the primary amine of the N ‐acyl‐ N ‐tosylhydrazine was shown to be a soft nucleophile. The similar bromohydrazidation reaction of γ,δ‐unsaturated N ‐acyl‐ N ‐tosylhydrazine resulted in O‐cyclization to give a lactone ring instead of N‐cyclization to give a hydropyridazine ring system; however, the intramolecular hydrazidopalladation reaction predominantly afforded a hydropyridazine ring. The established catalytic hydrazidopalladation reaction was applicable to several multisubstituted alkenes to construct a tetrasubstituted carbon center possessing a nitrogen group.