Effects of hexamethylphosphoric triamide (hempa) upon allylic grignard reagents: Synthesis of long chain alkenol acetates

Abstract

E or Z allylic Grignard reagents reacted with allylic halides in tetrahydrofuran-Hempa to give products in which the double bond from the organometallic fragment was predominantly Z. Protonation of the allylic Grignard reagents gave an increased proportion of A2-alkene and a higher ratio of Z:E isomers when Hempa was added.

Insect Pheromones: A Critical Review of Recent Advances in Their Chemistry, Biology, and Application

“…Insect Pheromones: A Critical Review of Recent Advances mediates (232)(233)(234)(235)(236), by allylic Grignard coupling (232,237), and by Wittig reaction (234,238). SONNET (239) isomerized the 7Z,llZ-and 7Z,llE-isomers (as their tetrahydropyranyl ethers) to the 7E,l1E-and 7 E, lIZ-isomers, respectively, by treatment of the corresponding bisepoxides with lithium diphenylphosphide and then methyl iodide.…”

“…SILVERSTEIN et al (51,136) began with the dithiane derivative of 3-methyl-2-butenal (260) and proceeded as in Scheme 47. RILEY et al (142) coupled (260) with (237) in the presence of zinc, and KARLSEN et al (138) coupled (244) Scheme 53…”