Regioselective cycloaddition of 3-azatrienes with enamines. Synthesis of pyridines derived from β-aminoacids
摘要:
Aza-Wittig reaction of N-vinylic phosphazenes with alpha,beta-unsaturated aldehydes leads to the formation of 3-azatrienes through a [2+2]-cycloaddition-cycloreversion process. Subsequent, regioselective [4+2]-cycloaddition of 3-azatrienes with pyrrolidinocycloalkanone affords bicyclic dihydropyridines and pyridines in a regioselective fashion. 2-Heterodiene moiety of azatriene is involved in the formation of the six-membered ring skeleton of pyridine derivatives. (c) 2006 Elsevier Ltd. All rights reserved.
Aza-Wittig reaction of N-vinylic phosphazenes with carbonyl compounds. Azadiene-mediated synthesis of dihydropyridines and pyridines
作者:Francisco Palacios、Gloria Rubiales
DOI:10.1016/0040-4039(96)01352-4
日期:1996.8
diphenylmethylphosphine 4 with carbonylcompounds leads to the formation of 2-azadienes derived from β-aminoacids 5. Dimerization of 2-azadienes 5c,d and reaction of compounds 5 with phosphazene 4 or enemine 6 affords substituted dihydropyridines 7 and 8. Aza-Wittig reaction of phosphazenes 4 with α,β-unsaturated aldehydes gives 3-azatrienes 12, which are easily converted into pyridines 13.
Aza-Wittig reaction of N-vinylic phosphazenes with alpha,beta-unsaturated aldehydes leads to the formation of 3-azatrienes through a [2+2]-cycloaddition-cycloreversion process. Subsequent, regioselective [4+2]-cycloaddition of 3-azatrienes with pyrrolidinocycloalkanone affords bicyclic dihydropyridines and pyridines in a regioselective fashion. 2-Heterodiene moiety of azatriene is involved in the formation of the six-membered ring skeleton of pyridine derivatives. (c) 2006 Elsevier Ltd. All rights reserved.