Chen, Chin H.; Fox, John L.; Lippert, Joseph L., Journal of Heterocyclic Chemistry, 1987, vol. 24, p. 931 - 932
作者:Chen, Chin H.、Fox, John L.、Lippert, Joseph L.
DOI:——
日期:——
CHEN, CHIN H.;FOX, JOHN L.;LIPPERT, JOSEPH L., J. HETEROCYCL. CHEM., 24,(1987) N 4, 931-932
作者:CHEN, CHIN H.、FOX, JOHN L.、LIPPERT, JOSEPH L.
DOI:——
日期:——
A comparative study of the interaction of salicylaldehydes with phosphonoacetates under Knoevenagel reaction conditions. Synthesis of 1,2-benzoxaphosphorines and their dimers
作者:Anka Bojilova、R. Nikolova、Christo Ivanov、Nestor A. Rodios、A. Terzis、C.P. Raptopoulou
DOI:10.1016/0040-4020(96)00748-x
日期:1996.9
The reaction of salicylaldehydes 5 with phosphonoacetates 6 gives the coumarin-3-phosphonates 7 and the 1,2-benzoxaphosphorine-3-carboxylates 8 in yields and 7:8 ratios depending on the reaction conditions. A mechanistic explanation is given for the stereoselectivity of these reactions. Irradiation of compounds 8 or direct exposure to sunlight causes their head-to-tail dimerization, giving the dimers
Diethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the centrosymmetric stereoisomer 6 predominates over the non symmetric P-epimer 7.