The scope of enantioselective allylations employing Nakamura's allylzinc-bisoxazoline reagent was examined by performing allylations of a selection of readily available ketones. Low-to-moderate ee's were observed, and a computational study was conducted to rationalize the results. Examination of transition structures of previously performed allylations that proceeded with high ee revealed the importance of both local and global control elements in these successful reactions. The ability of density functional theory methods to estimate the enantioselectivity of these asymmetric ketone allylations was established. All allylations that were studied computationally exhibited low (<5 kcal/mol) activation barriers, a result that is consistent with the highly reactive nature of Nakamura's reagent.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.bmcl.2010.11.121 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Viedma deracemization mechanisms in self-assembly processes.
Phys Chem Chem Phys
January 2025
Laboratoire Softmat, UMR au CNRS no 5623, Université Paul Sabatier, F-31062 Toulouse, France.
Simulations on an ODE-based model shows that there are many common points between Viedma deracemization and chiral self-assemblies of achiral building blocks towards chiral nanoparticles. Both systems occur in a closed system with energy exchange but no matter exchange with the surroundings and show parallel reversible growth mechanisms which coexist with an irreversible cluster breaking (grinding). The various mechanisms of growth give rise to the formation of polymerization/depolymerization cycles while the consecutive transformation of achiral monomer into chiral cluster results into an indirect enantioselective autocatalysis.
View Article and Find Full Text PDFCatalytic Asymmetric 1,4-Hydrocarbonation of 1,3-Enynes via Photoredox/Cobalt/Chromium Triple Catalysis.
Angew Chem Int Ed Engl
January 2025
Shanghai Jiao Tong University, Chemistry, 800 Dongchuan RD. Minhang District, 200240, Shanghai, CHINA.
A synergistic photoredox/cobalt/chromium triple catalysis system for regioselective, enantioselective, and diastereoselective 1,4-hydrocarbonation of readily available 1,3-enyne precursors was explored, providing a modular synthetic platform for various trisubstituted axially chiral allenes bearing an extra central chirality. The protocol features a broad substrate scope, good functional group tolerance, excellent selectivity, and mild reaction conditions. Furthermore, a possible reaction mechanism is proposed based on numerous control experiments and density functional theory calculations.
View Article and Find Full Text PDFThe Carbene Chemistry of -Sulfonyl Hydrazones: The Past, Present, and Future.
Chem Rev
January 2025
Department of Chemistry, Northeast Normal University, Changchun 130024, China.
-Sulfonyl hydrazones have been extensively used as operationally safe carbene precursors in modern organic synthesis due to their ready availability, facile functionalization, and environmental benignity. Over the past two decades, there has been tremendous progress in the carbene chemistry of -sulfonyl hydrazones in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Many carbene transfer reactions of -sulfonyl hydrazones are unique and cannot be achieved by any alternative methods.
View Article and Find Full Text PDFPd-catalyzed Asymmetric Hydrogenolysis Rearrangement of Allylic Esters to Access Axially Chiral Olefins.
Angew Chem Int Ed Engl
January 2025
Dalian University of Technology, School of Chemical Engineering, No 2 Linggong Road,Ganjingzi District, 116024, Dalian, CHINA.
The Pd-catalyzed asymmetric hydrogenolysis rearrangement of allylic acetates using (s-Bu)3BHK has been described, achieving the synthesis of axially chiral alkylidene cycloalkanes with excellent enantioselectivities (up to 99% ee) and a wide substrate scope (30 examples of cyclohexanes and cyclobutanes). To the best of our knowledge, this is the first time to achieve synthesis of axially chiral olefins via asymmetric hydrogenolysis of allylic acetates. This methodology not only offers a novel synthetic pathway for non-atropisomeric axially chiral structures but also highlights the potential of asymmetric hydrogenolysis as a powerful tool in synthetic organic chemistry.
View Article and Find Full Text PDFPalladium(II)-Catalyzed Enantioselective Ring Opening of Oxabenzonorbornadienes via Domino Aminopalladation of Alkynylanilines.
Org Lett
January 2025
College of Materials and Energy, South China Agricultural University, 510642 Guangzhou, China.
We report herein a robust enantioselective ring opening coupling of oxabenzonorbornadienes via Pd(II)-catalyzed domino cyclization of alkynylanilines, which features the formation of three covalent bonds and two contiguous stereocenters with excellent enantio- and diastereoselectivity and a broad substrate scope. The good functional group tolerance of this domino desymmetrization strategy enables efficient late-stage transformation of natural product-derived alkynylanilines. The resulting indolated dihydronaphthols could serve as a valuable platform to streamline the diversity-oriented synthesis of other valuable enantioenriched tetrahydronaphthalene derivatives.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!