Preparation of (Z)-Alkenes, Ketones, and Alkynes via Trialkyltin Chloride Induced Intramolecular Transfer Reaction of Lithium 1-Alkynyltrialkylborates. Stereoselective Synthesis of the Sex Pheromones of the Douglas Fir Tussock Moth, the Gipsy Moth, and the Wild Silkmoth Antheraea poly...

Article abstract of DOI:10.1021/jo00200a032

Trialkyltin chloride was used to induce selective migration of a primary alkyl group from the boron atom to the adjacent acetylenic carbon atom of lithium 1-alkynyltrialkylborate complexes derived from B-alkyl-9-borabicyclo<3.3.1>nonanes and 1-lithio-1-alkynes.Protonolysis of the resultant olefinic intermediate substituted with boron and tin functionalities on the adjacent vinyl carbon atoms provided the corresponding (Z)-alkene.Oxidation or iodination afforded the corresponding ketone or alkyne, respectively.The high selectivity of 9-borabicyclo<3.3.1>nonane as ahydroborating agent toward the terminal double bond allowed easy incorporation of internal double bond and triple bond into the alkyl group of the starting B-alkyl-9-borabicyclo<3.3.1>nonane.Various types of diene, enyne, enone, ynone and diyne were synthesized.These reactions were also successfully adopted for the stereoselective synthesis of sex pheromones of the Douglas fir tussock moth, the gypsy moth, and the wild silkmoth Antheraea polyphemus.