Reaction of diethylalkynylalane reagents with conjugated enones. 1,4 Addition of acetylene units to simple .alpha.,.beta.-unsaturated ketones

Abstract

than that observed* with the 11,15-bistetrahydropyranyl ether of prostaglandin Fia (4).

1, 4-Addition of Terminal Alkynes to Conjugated Enones in Water Using Green Catalyst Bis[(l)prolinato-N,O]Zn—An Environmentally Benign Protocol

“…The most common cuprate chemistry and dilithium trialkynylcuprate complexes fail to effect the conjugate addition of an alkynyl group to a conjugated enone [3,4]. Numerous attempts have been made to bridge this gap in synthetic methodology [5][6][7][8][9][10][11][12][13][14]. In each of these cases, acetylides must be generated by deprotonation, which requires stoichiometric quantities of at least one metal.…”

Five-coordinate organoaluminum acetylides and crystal structure of the hydrosylate, [Salophen(tBu)Al]2O

“…Since the first aluminum acetylide was reported in 1960 [1], aluminum acetylides have been used as versatile tools in organic synthesis [2][3][4]. For instance, alkynyldiethyl alanes have been used to alkynylate acyclic epoxides [2] and diethylalkylnylalane reagents have been employed to add acetylene units to simple a,b-unsaturated ketones [3].…”

Stereoselective Conjugate Addition Reactions Using In Situ Metallated Terminal Alkynes and the Development of Novel Chiral P,N-Ligands

“…30 In analogy to the Nagata hydrocyanation reaction which employs Et 2 AlCN for a regioselective 1,4-addition of cyanide to enones, 31 preformed aluminum alkynylides Et 2 AlCCR (prepared by transmetallation of the lithiated alkynes to diethylaluminum chloride) underwent conjugate addition to ,-unsaturated ketones. The products were obtained at room temperature in a mixture of ligroin/diethyl ether in 30-95% yield.…”