Arylation of 2-substituted 2-alkenals and 3-substituted 2-cyclohexen- and 2-cyclopenten-1-ones can effectively and regioselectively proceed at their γ-position by treatment with aryl bromides in the presence of a palladium catalyst and a base.
Ligand Control of Palladium‐Catalyzed Site‐Selective α‐ and γ‐Arylation of α,β‐Unsaturated Ketones with (Hetero)aryl Halides
作者:On Ying Yuen、Chau Ming So
DOI:10.1002/anie.202010682
日期:2020.12.21
describes the first palladium‐catalyzed, site‐selective α‐ and γ‐arylation of α,β‐unsaturated ketones with (hetero)arylhalides. A wide range of hetero(aryl)halides coupled with α,β‐unsaturated ketones, and transformation into the arylated products proceeded with excellent to good yields. The site selectivity of the reaction is switchable by simply changing the phosphine ligand to access either α‐arylated
Reaction de wittig-horner entre phosphonates et cyclohexenones β-substituees.
作者:Serge Geribaldi、Michel Rouillard
DOI:10.1016/s0040-4020(01)80938-8
日期:1991.1
attempted in order to prepare α,β,γ,δ-unsaturated nitriles via the Wittig-Horner reaction of β-substituted cyclohex-2-en-1-ones with diethyl cyanomethyl phosphonate. Among them, the one using NaH as base in refluxing THF gives only the products resulting from carbonyl attack, in good yields. The stereochemistry of the reaction is discussed.
Arynic condensations of ketone enolates. 15. New synthetic applications of the condensation of .alpha.,.beta.-unsaturated ketone enolates on benzyne
作者:Munir Essiz、Gerald Guillaumet、Jean Jacques Brunet、Paul Caubere
DOI:10.1021/jo01290a007
日期:1980.1
1H NMR utilization of through-space effects in configurational assignments. I—application to nitriles; determination of the separate effects of the electric field and anisotropy of the CN group
AbstractThe changes in chemical shift induced by isomerization for all the ring protons of the Z‐ and E‐5,5‐dimethyl‐2‐cyclohexenylidene acetonitriles depend only on the through‐space effects of the cyano group. The configurational assignments were made taking into consideration the anisotropic and electric field effects, either separately or together. In the first case, the total effects are ΔXCNT=−14.7×10−6cm3 mol−1 and bμCNT=14.7×10−30 cm3, respectively. The second approach allows the estimation of the values ΔXCN=−4.9 × 10−6 cm3 mol−1 and bμCN=9.8 × 10−3 cm3, reflecting the combined contributions of magnetic anisotropy and electric field to the total effect.