A new protocol has been developed for the borylation of conjugated alkenyl methyl ethers using B2Pin2 via C–O bond cleavage catalyzed by Ni(II). In this cross-coupling reaction, both E/Z isomers of alkenyl ethers are converted into (E)-alkenyl boronic esters with good reactivity. This transformation exhibits high chemoselectivity in the presence of competitive C–O bonds such as aryl ether, ester, amide
Synthesis and Acid-Catalyzed Cyclization of 2-Alkenylstilbenes: a New Approach to the Substituted Indenes
作者:Wei Ding、Xiaoxin Shi、Xia Lu
DOI:10.1002/cjoc.201500587
日期:2015.11
A base‐catalyzed ring‐opening of 1‐benzylisochromans 1 firstly produced 2‐alkenylstilbenes 2, which then underwent a mild acid‐catalyzed intramolecular cyclization to furnish 1,2‐disubstituted indenes 3 in high yields. Subsequently, a base‐catalyzed isomerization of the 1,2‐disubstituted indenes 3 afforded the more stable 2,3‐disubstituted indenes 4 in almost quantitative yields.
A new one pot protocol has been developed for the reductive silylation of alkenyl methyl ethers using Et3Si–BPin and HSiEt3 with nickel(II) catalyst. Styrene type methyl ethers, multi-substituted vinyl methyl ethers, heterocycles and unconjugated vinyl ethers are all tolerated to form alkyl silanes. Mechanistic study reveals that it is a cascade of a C–O bond silylation and vinyl double bond hydrogenation
Synthesis of deoxybenzoins from β-alkoxy styrenes and arylboronic acids via palladium-catalyzed regioselective Heck-arylation reactions
作者:Rapelly Venkatesh、Aswathi C. Narayan、Jeyakumar Kandasamy
DOI:10.1039/d4ob00616j
日期:——
Palladium-catalyzed synthesis of deoxybenzoin derivatives from styryl ethers and arylboronicacids is reported. The reaction proceeds under mild conditions in the presence of TEMPO and provides the desired products in good to excellent yields. Simple operation, broad substrate scope, and functional group tolerance are the salient features of the developed methodology.
据报道,钯催化从苯乙烯醚和芳基硼酸合成脱氧安息香衍生物。该反应在 TEMPO 存在下在温和条件下进行,并以良好至优异的产率提供所需产物。操作简单、底物范围广泛和官能团耐受性是所开发方法的显着特征。
Pd(II)-Catalyzed Sequential C–C/C–O Bond Formations: A New Strategy to Construct Trisubstituted Furans
Palladium-catalyzed oxidative difunctionalization of enol ethers with 1,3-dicarbonyl compounds to construct trisubstituted furans in one step under mild conditions is described. The reaction is thought to proceed through a C-C bond formation along with a C-O bond closing the ring structure. Oxygen is the sole oxidant regenerating the Pd(II) catalyst.