126579-07-5Relevant articles and documents
1,5-Sigmatropic Rearrangements of Diels-Alder Adducts in the Reaction of Alkatrienylphosphonates with Alkyl Acetylenecarboxylates - A New Method for the Synthesis of Benzyl- and Phenylphosphonates
Mondeshka, Diana,Tancheva, Chonka,Angelov, Christo
, p. 1381 - 1386 (2007/10/02)
The reaction of dialkyl (3-methyl-1,2,4-pentatrienyl)- and dialkyl (3-methyl-1-vinyl-1,2-butadienyl)phosphonic acids 1a-d and 5a, b respectively, with alkyl esters of the acetylenecarboxylic acids 2a - d proceeds via 1,5-sigmatropic rearrangement and aromatization of the initially formed Diels-Alder adducts.The reaction with the unsymmetrical dienophiles 2a, b occurs with preferred formation of the cycloadducts A, leading to the benzylphosphonates 3a - h.The above reaction constitutes a new method for the preparation of difficultly accessible derivatives of the benzyl- and phenylphosphonic acids.The aromatic structures of the obtained compounds 3a - h, 4a - f, and 6a - d were proved by IR, mass, and 1H-NMR spectra.
