d domino hydrosilylation of substrates carrying unsaturated functionalities in a proximal arrangement is presented to produce silacycles. Excellent levels of efficiency and selectivity were achieved in the cyclization by the deliberate choice of the hydrosilane reagents. The key to successful cyclic hydrosilylation is the reactivity enhancement of the second intramolecular hydrosilylation by a proximity
aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant C═Cbondcleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible
Pd-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>2</sup>) cross-coupling of Y(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>3</sub>(THF)<sub>2</sub> with vinyl bromides and triflates
作者:Guilong Cai、Zhibing Zhou、Wenchao Wu、Bo Yao、Shaowen Zhang、Xiaofang Li
DOI:10.1039/c6ob01765g
日期:——
with vinyl bromides and triflates has been developed for efficient synthesis of various allyltrimethylsilanes. The cross-coupling reaction was conducted at room temperature with low catalyst loading of either Pd(PPh3)4 or Pd(PPh3)2Cl2, and exhibited high efficiency and a broad substrate scope. In combination with the cross-coupling by the Lewis-acid catalyzed Hosomi–Sakurai reaction, a novel three-component
highly efficient Pd/Xiang-Phos catalyzedenantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with up to 97 % ee. The sterically bulky and electron-rich (S,Rs)-NMe-X2 ligand is responsible for the excellent reactivities and enantioselectivities. The salient features of this
A Cp2TiCl2-Me3Al (1 : 4) reagent system: An efficient reagent for generation of allylic titanocene derivatives from vinyl halides, vinyl ethers and carboxylic esters
Cp2TiCl2-Me3Al (a 1 : 4 ratio) reagent system in toluene for 3 days is found to be effective in generating allylic titanocene on treatment with vinyl halides, vinylethers and carboxylic esters in THF. The process for the generation of an allylic titanocene species from these starting materials was suggested to proceed through a formation of titanacyclobutane and the subsequent elimination of the halogen