Enantioselective Iridium-Catalyzed Allylic Substitution with 2-Methylpyridines
作者:Xi-Jia Liu、Shu-Li You
DOI:10.1002/anie.201700433
日期:2017.3.27
An enantioselective iridium‐catalyzed allylicsubstitution with a set of highly unstabilized nucleophiles generated in situ from 2‐methylpyridines is described. Enantioenriched 2‐substituted pyridines, which are frequently encountered in natural products and pharmaceuticals, could be easily constructed by this simple method in good yields and excellent enantioselectivity. The synthetic utility of the
描述了用2-甲基吡啶原位生成的一组高度不稳定的亲核试剂进行对映选择性铱催化的烯丙基取代。天然产物和药物中经常遇到的富含对映体的2-取代的吡啶可以通过这种简单方法以高收率和出色的对映选择性轻松地构建。吡啶产物的合成用途通过已报道的Na + / H +交换抑制剂的关键中间体的合成和(-)-番茄红素A的总合成得以证明。
Iridium-Catalyzed Enantioselective Allylic Substitution of Enol Silanes from Vinylogous Esters and Amides
作者:Ming Chen、John F. Hartwig
DOI:10.1021/jacs.5b09980
日期:2015.11.4
silanes of vinylogous esters and amides are classic dienes for Diels-Alder reactions. Here, we report their reactivity as nucleophiles in Ir-catalyzed, enantioselective allylic substitution reactions. A variety of allylic carbonates react with these nucleophiles to give allylated products in good yields with high enantioselectivities and excellent branched-to-linear ratios. These reactions occur with
乙烯基酯和酰胺的烯醇硅烷是 Diels-Alder 反应的经典二烯。在这里,我们报告了它们在 Ir 催化的对映选择性烯丙基取代反应中作为亲核试剂的反应性。各种烯丙基碳酸酯与这些亲核试剂反应,以良好的收率和高对映选择性和出色的支链与线性比率得到烯丙基化产物。这些反应以 KF 或醇盐作为添加剂发生,但机理研究表明这些添加剂不会激活烯醇硅烷。相反,它们用作促进环金属化以生成活性 Ir 催化剂的碱。由烯丙基碳酸酯的氧化加成产生的碳酸根阴离子可能会激活烯醇硅烷以触发它们作为亲核试剂与烯丙基铱亲电试剂反应的活性。
Enantioselective iridium catalyzed α-alkylation of azlactones by a tandem asymmetric allylic alkylation/aza-Cope rearrangement
作者:Xue-Dan Bai、Qing-Feng Zhang、Ying He
DOI:10.1039/c9cc01450k
日期:——
The development of an iridium catalyzedenantioselective α-alkylation of azlactones has been described. The reaction provides rapid access to a wide range of enantio-enriched quaternary carbon center allylated 2,4-diaryloxazol-5(2H)-ones in excellent yields with high enantioselectivities. The transformation was achieved through a tandem allylicalkylation/aza-Cope rearrangement, affording the desired
Asymmetric Rh(II)/Pd(0) Relay Catalysis: Synthesis of α-Quaternary Chiral β-Lactams through Enantioselective C–H Insertion/Diastereoselective Allylation of Diazoamides
作者:Liang-Zhu Huang、Zi Xuan、Hyun Ji Jeon、Zhen-Ting Du、Ju Hyun Kim、Sang-gi Lee
DOI:10.1021/acscatal.8b01687
日期:2018.8.3
α-quaternary chiral β-lactam moiety via Rh(II)/Pd(0)-catalyzed stereoselective relay catalytic reaction is reported. This asymmetric dual relay catalysis involves Rh(II)-catalyzed enantioselective intramoluecular C–H insertions of α-diazoamides, and sequential Pd(0)-catalyzed diastereoselective intermolecular allylic alkylation. Under mild reaction conditions, a broad range of α-quaternary allylated chiral