Palladium-catalyzed aerobic oxidative coupling of enantioenriched primary allylic amines with sulfonyl hydrazides leading to optically active allylic sulfones
A range of highly enantioenriched primary allylic amines underwent palladium-catalyzed oxidative coupling with sulfonyl hydrazides open to air at room temperature to give structurally diverse allylic sulfones in moderate to excellent yields with excellent retention of ee.
Iridium-Catalyzed Alkene-Selective Transfer Hydrogenation with 1,4-Dioxane as Hydrogen Donor
作者:Deliang Zhang、Tomohiro Iwai、Masaya Sawamura
DOI:10.1021/acs.orglett.9b01989
日期:2019.8.2
using 1,4-dioxane as a hydrogen donor is described. The use of 1,2-bis(dicyclohexylphosphino)ethane (DCyPE), featuring bulky and highly electron-donating properties, led to high catalytic activity. A polystyrene-cross-linking bisphosphine PS-DPPBz produced a reusable heterogeneous catalyst. These homogeneous and heterogeneous protocols achieved chemoselective transfer hydrogenation of alkenes over
Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities
A general, highly enantioselective Michael addition of nitroalkanes to α,β-unsaturated enones catalyzed by 9-amino(9-deoxy)-epi-quinine: a remarkable additive effect
作者:Siyang Liu、Qingqing Wang、Ling Ye、Zhichuan Shi、Zhigang Zhao、Xuejun Yang、Keyi Ding、Xuefeng Li
DOI:10.1016/j.tet.2016.07.008
日期:2016.8
A particularly general protocol for the organocatalytic asymmetric Michael addition of nitroalkanes to α,β-unsaturated enones is reported. The Michaelreaction proceeded smoothly and provided the desired adducts in moderate to excellent yields (55–99%) and good to excellent enantioselectivities (65–99% ee). The addition of readily available achiral base significantly enhanced the reactivity without
Chalk it up as a “Sc”andal: The asymmetricconjugateaddition of chalcone and “cinnamone” derivatives to nitromethane has been realized by using a simple and efficient scandium(III)–N,N′‐dioxide complex as the catalyst (see scheme). In the presence of 2–5 mol % catalyst loading, the corresponding products were formed in excellent yields (up to 99 %) and enantioselectivities (up to>99 % ee).