A Heteroleptic Dirhodium Catalyst for Asymmetric Cyclopropanation with α‐Stannyl α‐Diazoacetate. “Stereoretentive” Stille Coupling with Formation of Chiral Quarternary Carbon Centers
作者:Fabio P. Caló、Alois Fürstner
DOI:10.1002/anie.202004377
日期:2020.8.10
The heteroleptic dirhodium paddlewheel catalyst 7 with a chiral carboxylate/acetamidate ligand sphere is uniquely effective in asymmetric [2+1] cycloadditions with α‐diazo‐α‐trimethylstannyl (silyl, germyl) acetate. Originally discovered as a trace impurity in a sample of the homoleptic parent complex [Rh2((R )‐TPCP)4] (5 ), it is shown that the protic acetamidate ligand is quintessential for rendering
Guide to enantioselective dirhodium(II)-catalyzed cyclopropanation with aryldiazoacetates
作者:Kathryn M. Chepiga、Changming Qin、Joshua S. Alford、Spandan Chennamadhavuni、Timothy M. Gregg、Jeremy P. Olson、Huw M.L. Davies
DOI:10.1016/j.tet.2013.04.075
日期:2013.7
Catalytic enantioselective methods for the generation of cyclopropanes have been of long standing pharmaceutical interest. Chiraldirhodium(II) catalysts prove to be an effective means for the generation of diverse cyclopropane libraries. Rh2(R-DOSP)4 is generally the most effective catalyst for asymmetric intermolecular cyclopropanation of methyl aryldiazoacetates with styrene. Rh2(S-PTAD)4 provides
用于生成环丙烷的催化对映选择性方法长期以来一直是制药业的兴趣所在。手性二铑 (II) 催化剂被证明是生成各种环丙烷库的有效手段。Rh 2 ( R -DOSP) 4通常是重氮乙酸甲酯与苯乙烯的不对称分子间环丙烷化反应最有效的催化剂。Rh 2 ( S -PTAD) 4提供高水平的邻位取代芳基重氮乙酸酯的对映体诱导。不太成熟的 Rh 2 ( R -BNP) 4对 Rh 2 ( R-DOSP) 4和 Rh 2 ( S -PTAD) 4在催化 3-甲氧基取代的重氮基乙酸芳基酯的高度对映选择性环丙烷化反应中。苯乙烯的取代对环丙烷化的不对称诱导仅具有中等影响。
Tris(pentafluorophenyl)borane-Catalyzed Cyclopropanation of Styrenes with Aryldiazoacetates
作者:Joseph P. Mancinelli、Sidney M. Wilkerson-Hill
DOI:10.1021/acscatal.0c03218
日期:2020.10.2
the synthesis of cyclopropanes are critical for drug discovery, chemical biology, total synthesis, and other fields. Herein, we report the use of the strong sterically encumbered Lewis acid tris(pentafluorophenyl)borane as a catalyst for the cyclopropanation of unactivated alkenes using aryldiazoacetates. The cyclopropane products are synthesized using 10 mol % of the catalyst under mild conditions
Borane-Catalyzed Stereoselective C–H Insertion, Cyclopropanation, and Ring-Opening Reactions
作者:Ayan Dasgupta、Rasool Babaahmadi、Ben Slater、Brian F. Yates、Alireza Ariafard、Rebecca L. Melen
DOI:10.1016/j.chempr.2020.06.035
日期:2020.9
Lewisacidic boranes have been shown to be effective metal-free catalysts for highly selective reactions of donor-acceptor diazo compounds to a range of substrates. The reactions of α-aryl α-diazoesters with nitrogen heterocycles indole or pyrrole selectively generate C3 and C2 C–H insertion products, respectively, in good to excellent yields even when using unprotected indoles. Alternatively, benzofuran
Bis(imino)pyridine iron complexes for catalytic carbene transfer reactions
作者:Ban Wang、Isaac G. Howard、Jackson W. Pope、Eric D. Conte、Yongming Deng
DOI:10.1039/c9sc02189b
日期:——
bis(imino)pyridine iron complex, for the first time, is developed as an effective metal carbene catalyst for carbene transfer reactions of donor-acceptor diazo compounds. Its broad catalytic capability is demonstrated by a range of metal carbene reactions, from cyclopropanation, cyclopropenation, epoxidation, and Doyle-Kirmse reaction to O-H insertion, N-H insertion, and C-H insertionreactions. The