Aza-Wittig reaction of N-vinylic phosphazenes with carbonyl compounds. Azadiene-mediated synthesis of dihydropyridines and pyridines

Article abstract of DOI:10.1016/0040-4039(96)01352-4

Aza-Wittig reaction of N-vinylic phosphazenes derived from diphenylmethylphosphine 4 with carbonyl compounds 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.