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.
Asymmetric Synthesis of Deoxypropionate Derivatives via Catalytic Hydrogenolysis of Enantioenriched <i>Z</i>-Ketene Heterodimers
作者:Shi Chen、Ahmad A. Ibrahim、Mukulesh Mondal、Anthony J. Magee、Adam J. Cruz、Kraig A. Wheeler、Nessan J. Kerrigan
DOI:10.1021/acs.orglett.5b01391
日期:2015.7.2
A diagterosetective approach to deoxypropionate derivatives through Pd/C-catalyted hydrogenolysis of enantio enriched ketene heterodimers is described. Catalytic hydrogenolysis of the Z-isomer of ketene heterodimers facilitates access to, anti-deoxypropionate derivatives (10 examples With dr 7:1 to >20:1). Transfer of chirality from the Z-ketene heterodimer to an acid product was good to excellent in most as (78-99% ee for 12 examples).