Synthesis Of 3,4-Cyclopenta-1-Tetralones And α,β-Unsaturated Carbonyl Compounds

Among the family of tetralones,3,4-cyclopenta-1-tetralones are common skeletons found in a number of bioactive molecules. However, most of the precedented methods require the utilization of multi-step process, and the diastereoselective method remains to be an unmet goal. Herein, a straightforward, efficient, and highly diastereoselective method for the synthesis of 3,4-cyclopenta-1-tetralones has been realized via the copper-catalyzed coupling of 2-vinyl benzaldehydes with 3-alkenyl 2-bromocarbonyls. Subsequent reduction with L-selectride leads to the formation of benzannulated tricyclic alcohols, possessing four continuous stereogenic centers, in high yields with excellent diastereoselectivity. Indeed, three new C-C bonds and two new carbocycles can be constructed simultaneously via this reaction. It represents a novel, direct, and highly diastereoselective method for the synthesis of 3,4-cyclopenta-1-tetralones.Menwhile, the reigo- and stereoselective synthesis of α, β-unbsaturated carbonyl compounds is of significant importance. Based on our previous works on the regio- and stereoselective functionalization of ynol ethers, a regio- and stereoselective preparation of (E)-α,β-unbsaturated esters or amides has been realized via the silver-catalyzed coupling of expoxides with ynol ethers. The reaction is believed to be proceed via the Ag-catalyzed conversion of expoxides into aldehydes, [2+2] cycloaddition, and retro [2+2] cycloaddition domino process. The reaction proceeds under mild reaction conditions and tolerates a wide range of functional groups, which may be useful for organic synthesis.