由手性膦BINAP容易制备的手性膦氧化物BINAPO在三氯甲硅烷基化合物通过高价硅酸盐中间体的反应中表现出良好的催化活性。在催化量的BINAPO存在下,醛与烯丙基三氯硅烷的烯丙基化反应使烯丙基化的加合物具有良好的对映选择性(最高79%ee),其中二异丙基乙胺和四丁基碘化铵作为添加剂的组合对于加速催化循环至关重要。31氧化膦的1 P NMR分析表明,胺促进了氧化膦从硅原子上的解离。BINAPO还促进了二异丙基乙胺作为添加剂存在下醛与三氯甲硅烷基烯醇醚的对映体选择性醛醇缩合反应,从而以高非对映体和对映体选择性(最高syn / anti = 1 / 25,96%ee(anti))提供了相应的醛醇加合物。)。
One stone four birds: A single chiral primaryamine was found to catalyze unprecedented asymmetric retro‐aldol and transfer‐aldol reactions, leading to four different chiral aldol adducts from one common chiral source with up to 99:1 d.r. and 99 % ee (see scheme).
Surface-mediated solid phase reaction. Aldol reaction of silyl enol ethers with aldehydes on a solid surface of neutral alumina: selectivity for anti aldols
作者:Brindaban C. Ranu、Rupak Chakraborty
DOI:10.1016/s0040-4020(01)82382-6
日期:1993.6
The aldolreaction of trimethyl silylenolethers with aldehydes on the solid surface of neutral alumina under sonication without any solvent is found to proceed providing cross aldol products with anti selectivity.
o-Benzenedisulfonimide, a new strong bench-stable Brønsted acid, has been shown to efficiently catalyze the Mukaiyama aldol reaction of aldehydes or dimethyl acetals with silyl enol ethers under mild solvent-free reaction conditions.
Probing the Synergistic Catalytic Model: A Rationally Designed Urea-Tagged Proline Catalyst for the Direct Asymmetric Aldol Reaction
作者:Meeta Bhati、Kiran Kumari、Srinivasan Easwar
DOI:10.1021/acs.joc.8b00962
日期:2018.8.3
functional groups in the transition state of the enamine route to the asymmetric aldol reaction. The catalyst proved to be an excellent performer, delivering aldols in high yields and with excellent enantio- and diastereoselectivities using just 2 mol % loading in the presence of water; it also exhibited good levels of recyclability underaqueousconditions. The favorable results reveal the interesting
Simple and Facile l-Prolinamides Derived from Achiral Cycloalkylamines as Organocatalysts for the Highly Efficient Large-Scale Asymmetric Direct Aldol Reactions
simple catalyst can be efficiently used in large-scale reactions with the enantioselectivity being maintained at the same level, which offers great possibility for applications in industry.Graphical AbstractAll of the catalysts 1a–e synthesized fromachiral cycloalkylamines in a facile manner and their catalytic properties were studied in depth for the first time. All of the catalysts 1a–e exhibited great