2976-66-1Relevant academic research and scientific papers
Negishi coupling of secondary alkylzinc halides with aryl bromides and chlorides
Han, Chong,Buchwald, Stephen L.
supporting information; experimental part, p. 7532 - 7533 (2009/10/16)
(Chemical Equation Presented) An efficient palladium-catalyzed process has been developed for Negishi coupling of secondary alkylzinc halides with a wide range of aryl bromides and activated aryl chlorides. A palladium catalyst composed of a new biaryldialkylphosphine ligand, CPhos, effectively promotes the rate of the reductive elimination step relative to the rate of the undesired β-hydride elimination. The broad substrate scope and excellent ratio of the desired secondary to the undesired primary coupling product make this method a powerful and reliable tool forC(sp3)-C(sp2) bond formation.
Electronic effect, steric hindrance, and anchimeric assistance in oxidation of sulphides. Neighbouring-group participation through Sulphur-oxygen nonbonded interaction
Ruff, Ferenc,Kucsman, Arpad
, p. 1123 - 1128 (2007/10/02)
Using a set of sulphides o- and p-XC6H4SMe, the electronic effect, steric hindrance, and anchimeric assistance for electrophilic Cl+ addition by TsNHCI and O-transfer by NalO4 were investigated by a kinetic method. The steric effect and anchimeric assistance of the ortho-substituents were evaluated by comparing the reactivity of ortho- and para-substituted compounds (K = ko/kp). For neighbouringgroup activity the following order was obtained: CH2OH ~ CH2OMe ~ CH2CO2Me CH2CO2H ~ CH2NMe2 CH2C02 - ~ CHO CO2Me ~ CO2H COMe ~ CONH2 C02- Reaction rates show that the anchimeric assistance is governed by an S mellip; 0 or S ... N close contact developed in the transition state between oppositely polarized heteroatoms. Factors controlling neighbouringgroup participation through attractive non-bonded interactions are discussed.
