Enantioselective copper-catalyzed cyclization of γ-alkenylsulfonamides and a δ-alkenylsulfonamide in the presence of a range of vinyl arenes results in variously functionalized 2-substituted chiral nitrogen heterocycles via a formal alkene C-H functionalization process. Application of this reaction to the concise synthesis of a 5-HT(7) receptor antagonist is demonstrated.
Enantio- and diastereoselective addition of thioacetic acid to nitroalkenes via N-sulfinyl urea catalysis
作者:Kyle L. Kimmel、MaryAnn T. Robak、Stephen Thomas、Melissa Lee、Jonathan A. Ellman
DOI:10.1016/j.tet.2012.01.048
日期:2012.3
The enantioselective addition of thioacetic acid to nitroalkenes was achieved using N-sulfinyl urea catalysis. In this report, the scope of the reaction was extended to the enantio- and diastereoselective thioacetic acid addition to cyclic alpha,beta-disubstituted nitroalkenes. Additionally, the role of the sulfinyl group was investigated by replacing it with a variety of aryl and sulfonyl groups. Of 15 urea catalysts synthesized and tested, none displayed comparable selectivity to the sulfinyl catalysts, highlighting the importance of the sulfinyl group in attaining high enantioselectivity in the thioacetic acid addition. (C) 2012 Elsevier Ltd. All rights reserved.
Catalytic Enantioselective Alkene Aminohalogenation/Cyclization Involving Atom Transfer
作者:Michael T. Bovino、Sherry R. Chemler
DOI:10.1002/anie.201109044
日期:2012.4.16
the synthesis of chiral 2‐bromo, chloro, and iodomethyl indolines and 2‐iodomethyl pyrrolidines (see scheme). Stereocenter formation is believed to occur by enantioselective cis aminocupration and CX bond formation is believed to occur by atom transfer. The ultility of the products as versatile synthetic intermediates was demonstrated, as was a radical cascade cyclization sequence.
已解决的问题:标题反应用于合成手性 2-溴、氯和碘甲基二氢吲哚和 2-碘甲基吡咯烷(参见方案)。立体中心的形成被认为是通过对映选择性顺式 氨基氧化发生的,C X 键的形成被认为是通过原子转移发生的。证明了产品作为多功能合成中间体的实用性,以及自由基级联环化序列。
Stereoselective Copper-Catalyzed Intramolecular Alkene Aminooxygenation: Effects of Substrate and Ligand Structure on Selectivity
作者:Monissa C. Paderes、Sherry R. Chemler
DOI:10.1002/ejoc.201100444
日期:2011.7
A new protocol for diastereoselective copper-catalyzed intra-molecular alkene aminooxygenation, which provides methyleneoxy-functionalized disubstituted pyrrolidines and five-membered cyclic ureas from the corresponding γ-alkenyl sulfonamides and N-allylureas, is reported. In addition, some success was achieved in enantioselective desymmetrizations reactions. We discovered that the level of enantioselectivity
报道了一种非对映选择性铜催化分子内烯烃氨基氧化的新方案,该方案从相应的 γ-烯基磺酰胺和 N-烯丙基脲中提供亚甲氧基官能化的二取代吡咯烷和五元环脲。此外,对映选择性去对称化反应也取得了一些成功。我们发现对映选择性和非对映选择性的水平可以通过选择铜 (II) 配体和底物 N 取代基来调节。