A Stereoselective Hydroamination Transform To Access Polysubstituted Indolizidines
摘要:
Stereoselective, intramolecular, formal hydroamination of dienamines via directed hydroboration is reported. Four stereocenters are set in the process. Natural and unnatural indolizidine alkaloids can be synthesized from simple unsaturated amines using the title process.
A Stereoselective Hydroamination Transform To Access Polysubstituted Indolizidines
摘要:
Stereoselective, intramolecular, formal hydroamination of dienamines via directed hydroboration is reported. Four stereocenters are set in the process. Natural and unnatural indolizidine alkaloids can be synthesized from simple unsaturated amines using the title process.
Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer
作者:Casey B. Roos、Joachim Demaerel、David E. Graff、Robert R. Knowles
DOI:10.1021/jacs.0c01332
日期:2020.4.1
proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Non-covalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer
报道了一种对映选择性、基于自由基的方法,用于烯烃与磺酰胺的分子内加氢胺化。建议这些反应通过磺酰胺 NH 键的质子耦合电子转移 (PCET) 活化形成的 N 中心自由基进行。中性磺酰胺自由基与 PCET 事件中产生的手性磷酸之间的非共价相互作用被假设为后续 CN 键形成步骤中不对称诱导的基础,实现高达 98:2 er 的选择性。这些结果进一步支持了非共价相互作用在瞬态和高反应性开壳中间体的反应中增强立体选择性的能力。