title: Multicatalytic, asymmetric Michael/Stetter reaction of salicylaldehydes and activated alkynes.
abstract: We report the development of a multicatalytic, one-pot, asymmetric Michael/Stetter reaction between salicylaldehydes and electron-deficient alkynes. The cascade proceeds via amine-mediated Michael addition followed by an N-heterocyclic carbene-promoted intramolecular Stetter reaction. A variety of salicylaldehydes, doubly activated alkynes, and terminal, electrophilic allenes participate in a one-step or two-step protocol to give a variety of benzofuranone products in moderate to good yields and good to excellent enantioselectivities. The origin of enantioselectivity in the reaction is also explored; E/Z geometry of the reaction intermediate as well as the presence of catalytic amounts of catechol additive are found to influence reaction enantioselectivity.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Claire M
authors.initials: CM
authors.lastname: Filloux
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Lathrop
authors.forename: Tomislav
authors.initials: T
authors.lastname: Rovis