Catalytic Enantioselective Quick Route to Aldol-Tethered 1,6- and 1,7-Enynes from ω-Unsaturated Aldehydes

摘要: An effective asymmetric route to functionalized 1,6- and 1,7-enynes has been developed based on a direct cross-aldol reaction between w-unsaturated aldehydes propargylic (a,b-ynals) promoted by combined a,a-dialkylprolinol ether/Bronsted acid catalysis. This syner- gistic activation strategy is key accessing the correspond- ing aldol adducts with high stereoselectivity, both enantio- diastereoselectivity. The also proceeds well ketones (a,b-ynones) thus enabling stereocontrolled access corresponding tertiary alco- hols. utility of these adducts, which are difficult pre- pare through standard methodology, demonstrated their transformation into trisubstituted bicyclic enones using Pauson-Khand conditions.