Chiral allylsilanes derived from naturally occurring ?-amino acids

Natural occurring alpha-amino acids were transformed into (Z)-alkenes I [Boc = Me3CO2C; R = Me, CHMe2, CH2CHMe2, CHEtMe, CH2OSi(CMe3)Me2, indol-3-ylmethyl] by Wittig olefination of amino aldehydes BocNHCHRCHO with (Ph3PEt)Br in the presence of NaN(SiMe3)2. Metalation of I with butyllithium-potassium tert-butoxide gave, after reaction with trimethylsilyl chloride, chiral allylsilanes II. The condensation of II (R = Me, CHMe2) with acetyl chloride-titanium(IV) chloride is also reported.