Asymmetric Synthesis of Deoxypropionate Derivatives via Catalytic Hydrogenolysis of Enantioenriched Z-Ketene Heterodimers
摘要:
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).
Diastereoselective formation of β-hydroxyketones by the reduction of Ketene dimers
作者:Pei-Hsun Wei、Melanie A. Gary、Divya Nalla、Gero D. Harzmann、Ahmad A. Ibrahim、Kyle R. Dayak、Nessan J. Kerrigan
DOI:10.1016/j.tetlet.2012.12.011
日期:2013.2
method for the diastereoselective formation of β-hydroxyketones by the reduction of ketene dimers was developed. The reduction of ketene homodimers, derived from alkylarylketenes and dimethylketene, and ketene heterodimers, derived from methylketene and ethylphenylketene or diphenylketene, was investigated. Methylphenylketene dimer was reduced with optimal diastereoselectivity (dr = 6:1) using LiBH4
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.