Fine‐Tuning the Bicyclo[3.3.1]nona‐2,6‐diene Ligands: Second Generation 4,8‐Substituted Dienes for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions
作者:Vidmantas Bieliūnas、Sigitas Stončius
DOI:10.1002/cctc.202100638
日期:2021.9.7
C2-symmetric 4,8-endo,endo-bis(alkoxy) bicyclo[3.3.1]nona-2,6-diene ligands possessing additional 4,8-exo,exo substituents is reported. The 4,8-exo,exo groups provide a further element for fine-tuning of the ligand structure by enforcing conformational rigidity of the 4,8-endo,endo side chains. Such tetrasubstituted bicyclo[3.3.1]nona-2,6-dienes were employed as steering ligands in the rhodium-catalyzed arylation
A novel, C2-symmetric, chiral bis-cyclosulfinamide-olefin tridentate ligand in Rh-catalyzed asymmetric 1,4-additions
作者:Li Zhang、Mingchao Tan、Lihong Zhou、Qingle Zeng
DOI:10.1016/j.tetlet.2018.06.008
日期:2018.7
A C2-symmetric, chiral bis-cyclosulfinamide-olefin ligand composed of two 1-oxo-2,3-dihydro-1,2-benzisothiazole moieties with rigid skeletons and a conformationally flexible butenylene chain is disclosed for the first time. HRMS and 1H NMR analyses verify that the in situ-generated complex of the ligand and [Rh(C2H4)2Cl]2 possesses a rhodium (I) center coordinated to the tridentate ligand via two sulfinyl
首次公开了由两个具有刚性骨架和构象柔性的丁烯链的1-氧代-2,3-二氢-1,2-苯并噻唑结构部分组成的AC 2对称的手性双环亚磺酰胺-烯烃配体。HRMS和1 H NMR分析证实,该配体与[Rh(C 2 H 4)2 Cl] 2原位生成的络合物具有通过两个亚磺酰基部分和一个CdbndC键与三齿配体配位的铑(I)中心。手性配体在Rh催化的芳基硼酸与环己烯酮和环戊烯酮的不对称1,4-加成反应中提供了极高的对映选择性(高达> 99%ee)。与类似的手性二齿配体相比,三齿配体具有更高的对映选择性。
Preparation of <i>C</i><sub>2</sub>-Symmetric Bicyclo[2.2.2]octa-2,5-diene Ligands and Their Use for Rhodium-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids
C2-Symmetric bicyclo[2.2.2]octa-2,5-dienes containing benzyl, phenyl, and substituted phenyl groups at 2 and 5 positions were prepared enantiomerically pure by way of bicyclo[2.2.2]octane-2,5-dione as a key intermediate. These chiraldieneligands were successfully applied to rhodium-catalyzedasymmetric1,4-addition of arylboronic acids to α,β-unsaturated ketones. High enantioselectivity (up to 99%
Monodentate Non-<i>C</i><sub>2</sub>-symmetric Chiral <i>N</i>-Heterocyclic Carbene Complexes for Enantioselective Synthesis. Cu-Catalyzed Conjugate Additions of Aryl- and Alkenylsilylfluorides to Cyclic Enones
作者:Kang-sang Lee、Amir H. Hoveyda
DOI:10.1021/jo900589x
日期:2009.6.19
alkenyltetrafluorosilicate. Reactions proceed in the presence of 1.5 equiv of the aryl- or alkenylsilane reagents and 1.5 equiv of tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF). Desired products are isolated in 63−97% yield and 73.5:26.5−98.5:1.5 enantiomeric ratio (47%−97% ee). A major focus of the present studies is the design, evaluation, and development of new chiral imidazolinium salts and their
A New Type of Chiral Cyclic Sulfinamide-Olefin Ligands for Rhodium-Catalyzed Asymmetric Addition
作者:Quan Wen、Li Zhang、Jing Xiong、Qingle Zeng
DOI:10.1002/ejoc.201601206
日期:2016.11
A new type of chiral cyclic sulfinamide–olefin ligands, N-allylic 2,3-dihydro-1,2-benzoisothiazole 1-oxides, with 2,3-dihydro-1,2-benzoisothiazole 1-oxide as a unique chiral skeleton, is developed for the highly enantioselective rhodium-catalyzed asymmetric 1,4-addition of α,β-unsaturated cyclic carbonyl compounds and the 1,2-addition of benzil. Both enantiomers of the chiral cyclic sulfinamide–olefin