Faster, higher, stronger! The N‐heterocyclic carbene (NHC) catalyzed diastereo‐ and enantioselectivehydroacylation of cyclopropenes affords structurally valuable acylcyclopropanes. A new family of electron‐rich, 2,6‐dimethoxyphenyl‐substituted NHCs induces excellent reactivity and enantioselectivity. Preliminary kinetic studies unambiguously demonstrated the superiority of this family of catalysts
Synthesis of Chiral α,α-Disubstituted Cyclic Nitrones from Secondary Lactams
作者:Sora Iwamoto、Ayako Tokuyama、Shobu Hiraoka、Koya Takei、Koki Matsuzaka、Tsutomu Matsumoto、Noritaka Chida、Takaaki Sato
DOI:10.1246/bcsj.20230088
日期:2023.6.15
Bulletin of the Chemical Society of Japan, Ahead of Print.
日本化学会公报,印刷前。
Carbene‐Catalyzed Enantioselective Hydrophosphination of α‐Bromoenals to Prepare Phosphine‐Containing Chiral Molecules
作者:Rakesh Maiti、Jia‐Lei Yan、Xing Yang、Bivas Mondal、Jun Xu、Huifang Chai、Zhichao Jin、Yonggui Robin Chi
DOI:10.1002/anie.202112860
日期:2021.12.13
AbstractDisclosed herein is the first carbene‐organocatalyzed asymmetric addition of phosphine nucleophiles to the in situ generated α,β‐unsaturated acyl azolium intermediates. Our reaction enantioselectively constructs carbon–phosphine bonds and prepares chiral phosphines with high optical purities. The phosphine products are suitable for transforming to chiral ligands or catalysts with applications in asymmetric catalysis. The diarylalkyl or trialkyl phosphine products from our catalytic reactions, air‐sensitive and reactive in nature, can be trapped (and stored) in their sulfur‐oxidized form for operational simplicities.
Highly Asymmetric NHC-Catalyzed Hydroacylation of Unactivated Alkenes
NHC‐catalysis proto(n)type: The title reaction produces 21 different chroman‐4‐one‐type products in good yields and excellent enantioselectivities, in each case building up a new all‐carbon quaternary stereocenter (see scheme). Based on DFT calculations a mechanistic scenario involving proton transfer, possible transition states, and a mode of enantioinduction is presented.