A one-pot reaction sequence of sequential phosphine-promoted tandem annulations of aryl trifluoromethyl ketones and MBH (Morita-Baylis-Hillman) carbonates and DBU-mediated aminolysis was developed. This method provides a step-economical approach to trifluoromethylated dienamides with diverse structural complexity from readily available starting materials in moderate yields.Download high-res image (107KB)Download full-size imageA tandem one-pot protocol involving phosphine-promoted annulation reactions of aryl trifluoromethyl ketones and MBH (Morita-Baylis Hillman) carbonates, followed by DBU-mediated aminolysis with secondary alkylamines, was developed. This protocol enables a mild and cost-effective access to a range of trifluoromethylated dienamides from simple starting materials with acceptable yields.

A new approach to functionalized γ-butenolides based on reagent-controlled tandem reaction sequences of Morita–Baylis–Hillman-type vinyl epoxides is described. The nucleophilic addition of a tertiary phosphine to the electron-deficient alkene led to ring-opening of the epoxide followed by lactonization to produce phosphonium ylides, which could undergo Wittig olefination with aryl trifluoromethyl ketones and aryl aldehydes to give 3-alkenyl γ-butenolides in moderate to good yields and high E/Z selectivity. Tertiary amine promoted the Michael-type addition of carbon- and nitrogen-based nucleophiles to the vinyl epoxides followed by lactonization to provide diverse 3-substituted γ-butenolides.

A phosphine-promoted [3 + 2] cycloaddition from readily accessible MBH (Morita–Baylis–Hillman) carbonate and aryl trifluoromethyl ketone is described. The use of methyl vinyl ketone-derived allylic carbonate rather than common acrylate-derived counterpart renders the reaction pathway exclusive for 5-endo process, which enables the expeditious preparation of a range of trifluoromethylated 2,3-dihydrofuran in a chemospecific manner.An allylic phosphorus ylide cyclization with trifluoromethyl ketones not involving Wittig olefination is disclosed, which provided an expedient access to a series of CF3 2,3-dihydrofurans with excellent chemoselectivities.

A novel chemoselective phosphine-mediated tandem reaction between nonsubstituted MBH carbonates and aryl trifluoromethyl ketones is described. The product selectivity of the reaction is easily tunable by changing the ratios of the two reactants, and mono- or bicyclic bistrifluoromethylated vinyl γ-butenolide products can be prepared with good chemoselectivity in modest-to-good yields and diastereoselectivities. The formation of the bicyclic γ-butenolide structures via a one-pot four-step sequence under phosphine catalysis is unprecedented.