B-2'-ISOPRENYLDIISOPINOCAMPHEYLBORANE: AN EFFICIENT REAGENT FOR THE CHIRAL ISOPRENYLATION OF ALDEHYDES. A CONVENIENT ROUTE TO BOTH ENANTIOMERS OF IPSENOL AND IPSDIENOL

Article abstract of DOI:10.1016/0040-4039(90)87006-L

B-2'-Isoprenyldiisopinocampheylborane is prepared by metallation of isoprene with potassium 2,2,5,5-tetramethylpiperidide followed by sequential treatment with B-methoxydiisopinocampheylborane and boron trifluoride-etherate.Condensation of this reagent with aldehydes provides isoprenylated chiral alcohols.This methodology is utilized for an efficient one-pot synthesis of both enantiomers of the pheromones of the bark beetle Ips paraconfusus Lanier, ipsenol and ipsdienol in 96percent ee and 65percent isolated yields.