使用氧代铵盐作为催化剂,已开发出未活化的烯烃向烯酮的第一个催化氧化烯丙基转移。该反应将各种三和反双取代的烯烃转化成其相应的烯酮,并在环境温度下以双键的换位以良好的收率。使用较少受阻的氮杂金刚烷型氧铵盐作为催化剂,并使用两种不同的化学计量氧化剂(即碘代苯二乙酸盐和单过氧邻苯二甲酸镁六水合物(MMPP·6 H 2 O))的组合,对于有效促进烯酮的形成至关重要。
Enantioselective Ni/N-Heterocyclic Carbene-Catalyzed Redox-Economical Coupling of Aldehydes, Alkynes, and Enones for Rapid Construction of Acyclic All-Carbon Quaternary Stereocenters
作者:Wu-Bin Zhang、Guang Chen、Shi-Liang Shi
DOI:10.1021/jacs.1c12625
日期:2022.1.12
but their enantioselective construction remains a prominent challenge. In particular, multicomponent enantioselective couplings of simple precursors to acyclic all-carbon quaternary stereocenters are very rare. We describe herein an N-heterocyclic carbene (NHC)-Ni catalyzed redox-economical three-component reaction of aldehydes, alkynes, and enones that proceeds in a highly chemo-, regio-, and enantioselective
Oxazaborolidine-catalyzed enantioselective reduction of a-methylene ketones was efficiently carried out by using borane-diethylaniline as a stoichiometric reducing agent. The combination of this method and subsequent hydrogenation of thus-formed allylic alcohol improved stereoselectivity in the reduction of 24-oxocholesteryl ester to 24-(R)-hydroxycholesteryl ester.
Catalytic Oxygenative Allylic Transposition of Alkenes into Enones with an Azaadamantane‐Type Oxoammonium Salt Catalyst
The first catalyticoxygenativeallylictransposition of unactivated alkenes into enones has been developed using an oxoammoniumsalt as the catalyst. This reaction converts various tri- and trans-disubstituted alkenes into their corresponding enones with transposition of their double bonds at ambient temperature in good yields. The use of a less-hindered azaadamantane-type oxoammoniumsalt as the catalyst
使用氧代铵盐作为催化剂,已开发出未活化的烯烃向烯酮的第一个催化氧化烯丙基转移。该反应将各种三和反双取代的烯烃转化成其相应的烯酮,并在环境温度下以双键的换位以良好的收率。使用较少受阻的氮杂金刚烷型氧铵盐作为催化剂,并使用两种不同的化学计量氧化剂(即碘代苯二乙酸盐和单过氧邻苯二甲酸镁六水合物(MMPP·6 H 2 O))的组合,对于有效促进烯酮的形成至关重要。
A short and stereoselective synthesis of highly substituted cyclopropanes from α,β-unsaturated carbonyl compounds with dichloromethyl p-tolyl sulfoxide
The reaction of the α-sulfinyl carbanion of dichloromethyl p-tolyl sulfoxide with a variety of α,β-unsaturated carbonyl compounds gave highly substitutedcyclopropanes (up to five substituents) in good to high yields with high stereoselectivity.