Catalytic Asymmetric Heterodimerization of Ketenes
作者:Ahmad A. Ibrahim、Divya Nalla、Maxwell Van Raaphorst、Nessan J. Kerrigan
DOI:10.1021/ja211678m
日期:2012.2.15
In this Communication we describe an unprecedented catalytic asymmetric heterodimerization of ketenes of wide substrate scope. The alkaloid-catalyzed method provides access to ketene heterodimer beta-lactones and allows even two different monosubstituted ketenes to be cross-dimerized, with excellent enantioselectivity (17 examples with >= 90% ee) and excellent heterodimer regioselectivity observed in all cases.
Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations
作者:Shi Chen、Ahmad A. Ibrahim、Nicholas J. Peraino、Divya Nalla、Mukulesh Mondal、Maxwell Van Raaphorst、Nessan J. Kerrigan
DOI:10.1021/acs.joc.6b01481
日期:2016.9.2
scope exploration, protocol innovations (including double in situ ketene generation for 7 examples), and an application to a cinnabaramide A intermediate are described. The addition of lithium perchlorate (1–2 equiv) as an additive to the alkaloid catalyst system was found to favor formation of the E isomer of the ketene heterodimer. Ten examples were formed with moderate to excellent (E)-olefin isomer
Mechanistic Investigations of the Pd‐Catalyzed Hydrogenolysis of Ketene Heterodimer β‐Lactones
作者:Manashi Panda、Mukulesh Mondal、Shi Chen、Ahmad A. Ibrahim、Dylan J. Twardy、Nessan J. Kerrigan
DOI:10.1002/ejoc.202000976
日期:2020.9.22
Catalytic hydrogenolysis of the Z‐isomer of a series of aryl‐substituted ketene heterodimers facilitated access to deoxypropionate derivatives, favoring the anti‐isomer, and with excellent transfer of chirality. Anti‐β‐elimination and an anti‐selective hydrogenation of an E‐olefin intermediate are proposed to be key steps.