Asymmetric synthesis of bicyclic ketones having an angular substituent via Ti(II) alkoxide-mediated tandem cyclization of trisubstituted olefinic substrates

[reaction: see text] Angularly substituted, optically active bicyclic ketones of up to 94% ee were prepared by the Ti(II) alkoxide-mediated tandem cyclization of open-chain substrates, that is, 8-phenylmenthyl enynoates having a trisubstituted double bond.