Diastereoselective Trapping of Transient Carboxylic Oxonium Ylides with α,β‐Unsaturated 2‐Acyl Imidazoles
作者:Mengchu Zhang、Tianyuan Zhang、Dan Zhang、Wenhao Hu
DOI:10.1002/adsc.202000701
日期:2020.11.4
By developing a diastereoselective reaction of cyclopropene carboxylic acids with α,β‐unsaturated 2‐acylimidazoles, we reported here a Michael‐type trapping of transient carboxylic oxonium ylides. This transformation provides a direct approach for the construction of valuable γ‐butenolide derivatives in good yields (60–99%) with high diastereoselectivities (up to >95:5 dr) under mild reaction conditions
Mirror mirror on the wall: By taking advantage of the unique structural features of L‐DNA, the first examples of left‐helical enantioselective induction in the field of DNA‐based asymmetriccatalysis were realized. Most importantly, this approach is the only one that allows a reliable and predictable access to both enantiomers for any given reaction.
Effect of ligand sequence-specific modification on DNA hybrid catalysis
作者:H. Zhou、D. Chen、J. K. Bai、X. L. Sun、C. Li、R. Z. Qiao
DOI:10.1039/c7ob01249g
日期:——
key to success for acquiring chiral materials. In recent years, DNA hybrid catalysts have attracted significant interest due to their excellent abilities in accelerating reactions and achieving high enantioselectivity. We report here that bipyridine linked with polyamide as a sequence-specific catalytic ligand was designed to perform a DNA hybrid asymmetric reaction. The products presented different stereoselectivities
The challenge in DNA-basedasymmetriccatalysis is to perform a reaction in the vicinity of the helix by incorporating a small-molecule catalyst anchored to the DNA in a covalent, dative, or non-covalent yet stable fashion in order to ensure high levels of enantio-discrimination. Here, we report the first generation of a DNA-based catalyst bound to a cellulose matrix. The chiral biomaterial is commercially
Direct Access to Highly Enantioenriched α-Branched Acrylonitriles through a One-Pot Sequential Asymmetric Michael Addition/Retro-Dieckmann/Retro-Michael Fragmentation Cascade
A highly enantioselective synthesis of alpha-branched acrylonitriles is reported featuring a one-pot sequential asymmetric Michael addition/retro-Dieckmann/retro-Michael fragmentation cascade. The method, which relies on a solid, bench-stable, and commercially available acrylonitrile surrogate, is practical, scalable, and highly versatile and provides a direct access to a wide range of enantioenriched nitrite-containing building blocks. Most importantly, the method offers a new tool to incorporate an acrylonitrile moiety in an asymmetric fashion.