Trans-selective olefin synthesis

Primarily trans-olefination has been achieved by rapid equilibration of erythro- and threo-betaines. The betaine ylides (I) are formed by the treatment of betaine-LiX adduct with PhLi or n-BuLi in 1:1 ether-tetrahydrofuran at -30 Deg. The equil. between the diastereoisomeric betaine ylides lies far to the threo-form, so that protonation gives mainly threo-betaine. Subsequent treatment with tert- BuOK gives almost pure trans-olefin. The yields of the trans- olefins were from 55-70% and the proportion of the trans-olefin in the mixt. was 89-99%. [on SciFinder (R)]


Published in:
Angewandte Chemie, International Edition, 5, 1, 126
Year:
1966
Keywords:
Note:
CAN 64:84024 33 Aliphatic Compounds Univ. Heidelberg,Germany. Journal written in English. 768-00-3 (2-Butene, 2-phenyl-, trans-); 873-66-5 (Benzene, propenyl-, trans-); 1005-64-7 (1-Butene, 1-phenyl-, trans-); 3909-96-4 (1,3-Pentadiene, 1-phenyl-, trans-); 6111-82-6 (1-Hexene, 1-phenyl-, trans-); 13389-42-9 (2-Octene, trans-); 14850-23-8 (4-Octene, trans-) (formation from threo-ylides)
Laboratories:




 Record created 2006-03-03, last modified 2018-01-27


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