Rhodium-Catalyzed Allylic Substitution Reactions with Indium(III) Organometallics
作者:Ricardo Riveiros、Rubén Tato、José Pérez Sestelo、Luis A. Sarandeses
DOI:10.1002/ejoc.201200104
日期:2012.5
novel rhodium-catalyzed allylic substitution reaction using indium organometallics is reported. Aryl- and heteroarylindium reagents reacted in THF at 80 °C with primary and secondary allyl halides and their derivatives under rhodium(I) catalysis to afford the α-substituted products in good yields and with high regio- and stereoselectivity. The reaction takes place with substoichiometric amounts of
A stereospecific route to olefins through sequential coupling reaction of Grignard reagents with 1-bromo-2-phenylthioethene in the presence of nickel or palladium catalysts
temperature sequential formation of two C–C bonds by reaction of aromatic or aliphatic Grignard reagents with (E)- or (Z)-1-bromo-2-phenylthioethene in the presence of nickel(II) or palladium(II) catalysts provides a novel stereospecific route to a variety of (E)- or (Z)-olefins of the R–CHCH–R and R1–CHCH–R2 type, with a stereoselectivity higher than 99% for the (E) isomers and in the range 95–98% or the (Z)
Brønsted Acid-Catalyzed Intramolecular Hydroarylation of β-Benzylstyrenes
作者:Xiao Cai、Amir Keshavarz、Justin D. Omaque、Benjamin J. Stokes
DOI:10.1021/acs.orglett.7b00958
日期:2017.5.19
triphenylmethylium tetrakis(pentafluorophenyl)borate as a convenient Brønsted acid precatalyst, β-(α,α-dimethylbenzyl)styrenes are shown to cyclize efficiently to afford a variety of new indanes that possess a benzylic quaternary center. The geminal dimethyl-containing quaternary center is proposed to be necessary to arm the substrate for cyclization through steric biasing.
“On water” sp3–sp2 cross-couplings between benzylic and alkenyl halides
作者:Valeria Krasovskaya、Arkady Krasovskiy、Anish Bhattacharjya、Bruce H. Lipshutz
DOI:10.1039/c1cc11087j
日期:——
Organic-solvent-free cross-couplings between benzylic and alkenylhalides have been developed. Various alkenylhalides can be efficiently benzylated by combining the precursor halides in the presence of Zn dust and a Pd catalyst at room temperature, in water as the only medium.
A novel chiral ligand mimicking N-Ar axial chirality, (S)-N-[2-(diphenylphosphanyl)naphthalen-1-yl]-2-(piperidinylmethyl)piperidine, was found to exhibit good enantioselectivity (up to 80% ee) in the asymmetric cross-coupling reaction of 1-phenylethylmagnesium chloride with β-bromostyrene derivatives. Additionally, this type ligand is appealing, because it allows the synthesis of a wide variety of analogues.