Preparation of syn-tertiary homoallylic alcohols utilizing allenyltitanocenes generated by reductive titanation of gamma-trimethylsilylpropargylic carbonates.

syn-Tertiary homoallylic alcohols were obtained by the reaction of alpha-silylallenyltitanocenes generated by the reductive titanation of gamma-silylpropargylic carbonates with Cp(2)Ti[P(OEt)(3)](2) with ketones and following desilylation and partial hydrogenation. High diastereoselectivity was observed when aromatic and alpha,beta-unsaturated ketones were employed.

Titanocene(II)-promoted, one-pot, three-component coupling of thioacetals, alkynyl sulfones, and carbonyl compounds: highly stereoselective formation of tert-homopropargyl alcohols.

Titanocene alkylidene complexes, generated by desulfurizative titanation of thioacetals with Cp2Ti[P(OEt)3]2, reacted with alkynyl methyl sulfones to produce organotitanium species, which gave tert-homopropargyl alcohols with high diastereoselectivity on treatment with aromatic and alpha,beta-unsaturated ketones.