Benzylamine as Hydrogen Transfer Agent: Cobalt‐Catalyzed Chemoselective C=C Bond Reduction of β‐Trifluoromethylated α,β‐Unsaturated Ketones via 1,5‐Hydrogen Transfer
of β-CF3 -α,β-unsaturatedketones using benzylamine as hydrogen transfer agent involving intramolecular 1,5-hydrogen transfer is reported. The reaction proceeded smoothly with a relatively wide range of substrates including those bearing aromatic heterocycles such as a furyl ring system in high yields (74-92 %). This provides an efficient method for the synthesis of β-CF3 saturated ketones in one-pot
作者:Amparo Sanz-Marco、Gonzalo Blay、Carlos Vila、José R. Pedro
DOI:10.1021/acs.orglett.6b01494
日期:2016.8.5
The enantioselective conjugate alkynylation of β-aryl-β-trifluoromethyl enones has been carried out using terminal alkynes and diethylzinc in the presence of 3,3′-bis(perfluorophenyl)BINOL as the chiral ligand to give the corresponding ketones bearing a trifluoromethylated propargylic quaternary stereocenter with fair to good enantioselectivities. Enones bearing a bulky 2-naphthyl attached to the carbonyl
Diastereoselective and Enantioselective Epoxidation of Acyclic β-Trifluoromethyl-β,β-Disubstituted Enones by Hydrogen Peroxide with a Pentafluorinated Quinidine-Derived Phase-Transfer Catalyst
efficient catalytic asymmetric epoxidation of β‐trifluoromethyl‐β,β‐disubstituted unsaturated ketones has been achieved by a pentafluorine‐substituted phase‐transfer catalyst with hydrogenperoxide (30%). Thus, the β‐trifluoromethyl‐α,β‐epoxy ketones with a quaternary carbon centre were obtained in excellent diastereoselectivities (up to 100:1 dr) and excellent enantioselectivities (up to 99.7% ee). Low catalyst
Efficient Access to Trifluoromethyl Diarylpyrrolines and their N-Oxides through Enantioselective Conjugate Addition of Nitromethane to β,β-Disubstituted Enones
The cupreidinium salt 1 catalyzes the highlyenantioselectiveconjugateaddition of nitromethane to β‐aryl‐β‐trifluoromethyl aryl enones (2). The biologically important chiral pyrrolines 4 and N‐oxide 5, having a trifluoromethylated all‐carbon quaternary chiral center, were easily synthesized from the key intermediate (R)‐3 in high to excellent yields. M.S.=molecular sieves.
An efficient transition-metal-free hydrodefluorination reaction of trifluoromethyl alkenes for accessing gem-difluoroalkenes is developed. It was surprising to find that the phosphoryl anion is able to mediate the defluorination.