Iododesilylation of TIPS-, TBDPS-, and TBS-Substituted Alkenes in Connection with the Synthesis of Amphidinolides B/D

Abstract

The C–Si bonds of triisopropylsilyl-substituted alkenes, 1,3-dienes, and related multifunctional substrates, as well as analogous C–TBDPS and C–TBS bonds, are readily and chemoselectively cleaved with NIS (or other sources of I+, such as N-iodosaccharin, 1,3-diodohydantoin, and Ipy2BF4). The desired iodoalkenes are obtained stereospecifically without byproducts, provided that the reactions are carried out in CF3CHOHCF3 and, in general, with 30 mol % of Ag2CO3 (or AgOAc/2,6-lutidine) as an additive. Fragment C10–C18 of cytotoxic amphidinolides B1–B3 and D has been synthesized using this improved procedure