Chiral trialkoxysilanols derived from terpene alcohols.: Molecular structures of tris([(1S)-endo]-(−)-bornoxy)silanol and tetrakis((−)-menthoxy)silane

Terpene alcohols (−)-menthol and [(1S)-endo]-(−)-borneol react with SiCl4 in the presence of base to give (MenO)3SiCl (1) and (BorO)3SiCl (2) in high yields. Hydrolysis of 1 yields (MenO)3SiOH (4) and (MenO)4Si (3). Hydrolysis of 2 yields only (BorO)3SiOH (5). The crystal structures of 3 and 5 are reported.