Regiospecific Functionalization of Dimetalated Isopropenylacetylene, a Synthetic Equivalent of the Isoprene "Anion". An Efficient Synthesis of the Bark Beetle Pheromones (+/-)-Ipsenol and (+/-)-Ipsdienol

Article abstract of DOI:10.1021/jo00232a037

Regiospecific (mono)functionalization of dilithiated isopropenylacetylene LiC<*>CC(=CH2)CH2Li with a large number of electrophilic reagents ("E⁺")gave the compounds HC<*>CC(=CH2)CH2E in high yields.Coupling with (CH3)2CHCH2CH=O and (CH3)2C=CHCH=O, followed by partial reduction of the triple bond with activated zinc powder, gave the bark beetle pheromones ipsenol and ipsdienol, respectively, in >55percent overall yields.