Q. Wang et al., The simultaneous in-situ generation of aldehydes and phosphorus ylides: A convenient multi-step one-pot olefination protocol, EUR J ORG C, (12), 1999, pp. 3263-3268
The lithium alpha-(dimethylamino)alkoxides resulting from the nucleophilic
addition of an organolithium reagent to N,N-dimethylformamide are basic eno
ugh to deprotonate alkyltriphenylphosphonium salts suspended in tetrahydrof
uran. The aldehydes liberated by the spontaneous decomposition of the resul
ting alpha-amino alcohols (hemiaminals) undergo a Wittig reaction with the
simultaneously generated phosphorus ylides to afford olefins in excellent o
verall yields. This in situ method offers the unique advantage in its appli
cability to labile aldehydes which otherwise would become prey to (Z/E)-iso
merization or self-condensation processes.