An allylic isoprenoid C5 nucleophile for the synthesis of forskolin

Article abstract of DOI:10.1016/S0040-4039(97)01662-6

InCl₃-mediated coupling of δ-alkoxy allylic stannane 9b with aldehydes has been shown to give the α-coupling products in high yield, probably via two S(E)' processes. Most specifically, drimenal (rac-l) has been converted into labdane derivative 17 which is considered to be an important intermediate on the way to forskolin.