C-H Functionalization of Amino Alcohols by Osmium Tetroxide/NMO or TPAP/NMO: Protecting Group-Free Synthesis of Indolizidines (-)-223AB and 3-<i>epi</i>
-(-)-223AB
作者:Wei-Lun Chen、Lee-Ya Wang、Yu-Jang Li
DOI:10.1002/ejoc.201901494
日期:2020.1.9
perruthenate, with NMO provide N,O‐acetal moieties by trapping the resulting iminium ion with the alcohol. These two transformations were demonstrated in the protecting group free synthesis of indolizidines (–)‐223AB and 3‐epi‐(–)‐223AB, compounds found in dart‐frog poison.
Dynamic Biphasic Counterion Exchange in a Configurationally Stable Aziridinium Ion: Efficient Synthesis and Isolation of a Koga C<sub>2</sub>-Symmetric Tetraamine Base
作者:Matthew J. Frizzle、Sebastien Caille、Teresa L. Marshall、Kenneth McRae、Kelly Nadeau、Gary Guo、Steven Wu、Michael J. Martinelli、George A. Moniz
DOI:10.1021/op0602371
日期:2007.3.1
An efficient synthetic process for chiral tetraamine base (R,R)-5 is reported that leverages mechanistic understanding to enable control over key transformations. Specifically, a configurationallystable and observable aziridinium ion intermediate was found to undergo counterion exchange impacting the feasibility of the process. Mechanistic investigations revealed that both counterion exchange and
Thiyl Radical Mediated Racemization of Benzylic Amines
作者:Stéphanie Escoubet、Stéphane Gastaldi、Nicolas Vanthuyne、Gérard Gil、Didier Siri、Michèle P. Bertrand
DOI:10.1002/ejoc.200600120
日期:2006.7
Thiylradical mediated reversible H abstraction from the stereogenic center α to the nitrogen atom is a mild method to racemize benzylic amines. Owing to the sensitivity of atom-transfer reactions to enthalpic effects, a knowledge of both the S–H and the α-C–H bond dissociation energies is fundamental to select the thiol that is appropriate to abstract the hydrogen atom from a given amine. In the absence