Novel and Efficient Entry to γ-Aryl-Substituted γ,δ-Unsaturated Ketones, Amides, Nitriles, and Sulfones by Conjugate Additions of 2-Benzotriazolylethylsilanes

One-Pot Synthesis of Homoallylic Ketones from the Addition of Vinyl Grignard Reagent to Carboxylic Esters

“…11c Several methods exist for the construction of the γ,δunsaturated carbonyl unit. For example, 1,4-addition of lithium vinyl cuprates, 12 organoboranes, 13 2-benzotriazolyl-2-arylethylsilanes, 14 and R-zirconated vinylsilanes 15 silyl enol ethers 16 and various allylations of unsaturated compounds under ruthenium, 17 palladium, 18 and copper catalysis. 19 The Claisen-Cope 20 and Carroll rearrangements 21 and Wittig 22 methodology have also found utility in the construction of γ,δ-unsaturated carbonyl compounds.…”

“…Several methods exist for the construction of the γ,δ-unsaturated carbonyl unit. For example, 1,4-addition of lithium vinyl cuprates, organoboranes, 2-benzotriazolyl-2-arylethylsilanes, and α-zirconated vinylsilanes to α,β-unsaturated compounds has given homoallylic ketones in good yield. Alternative protocols include the allylation of silyl enol ethers and various allylations of unsaturated compounds under ruthenium, palladium, and copper catalysis .…”

1,2,3-Triazoles

“…Additions of lithiated silyl derivatives 404 to α,β-unsaturated compounds bearing electron-withdrawing substituents X provide silyl derivatives 407 with high 1,4-regioselectivity. Elimination of trimethylsilyl and benzotriazolyl groups facilitated by heating with CsF leads to γ,δ-unsaturated ketones, nitriles, sulfones, nitroalkanes, or amides 408 <1998JOC9987> . Formylation of intermediates 404 produces masked acroleins 409 that provide easy access to 2-substituted allyl alcohols 410 .…”