T. Kawashima et al., THE OLEFIN SYNTHESIS FROM BETA-HYDROXYALKYLPHOSPHONATES INDUCED BY FLUORIDES OR RELATIVELY WEAK BASES, Bulletin of the Chemical Society of Japan, 71(1), 1998, pp. 209-219
beta-Hydroxyalkylphosphonates, which were prepared readily from alkylp
hosphonates and carbonyl compounds, were treated with a fluoride ion s
uch as CsF or with relatively weak bases such as K2CO3 in N,N-dimethyl
formamide to give the corresponding olefins in good yields. One molar
equivalent of water to bases is effective for increasing the yields of
olefins. The stereochemistry of erythro-dimethyl (2-hydroxy-1-methyl-
2-phenyl)ethylphosphonate was determined by X-ray crystallographic ana
lysis. Use of threo-isomer gave (E)-olefin exclusively, while that of
erythro-enriched isomer afforded predominantly (Z)-olefin, indicating
that the present olefination proceeds stereospecifically in a manner o
f syn-elimination.