Preparation of Chiral Allenes through Pd-Catalyzed Intermolecular Hydroamination of Conjugated Enynes: Enantioselective Synthesis Enabled by Catalyst Design
作者:Nathan J. Adamson、Haleh Jeddi、Steven J. Malcolmson
DOI:10.1021/jacs.9b02637
日期:2019.5.29
surrogate to afford primary amines in a two-step/one-pot process. Examination of chiral catalysts revealed a high degree of reversibility in the C-N bond formation that negatively impacted enantioselectivity. Consequently, an electron-poor ferrocenyl-PHOX ligand was developed to enable efficient and enantioselective enyne hydroamination.
A versatile method for the preparation of allenic alcohols
作者:Gary E. Keck、R.R. Webb
DOI:10.1016/s0040-4039(00)87530-9
日期:1982.1
A convenient three step procedure to a variety of allenicalcohols is described, which relies on a highly unusual partitioning between two reaction pathways depending on the mode of addition of a reagent.
A Direct Synthesis of Allenes by a Traceless Petasis Reaction
作者:Devon A. Mundal、Kelly E. Lutz、Regan J. Thomson
DOI:10.1021/ja301489n
日期:2012.4.4
A one-pot synthesis of allenes by the 2-nitrobenzenesulfonylhydrazide-mediated coupling of hydroxyaldehydes or ketones with alkynyl trifluoroborate salts is reported. This mild process involves in situ formation of a sulfonylhydrazone that reacts with alkynyl trifluoroborates to generate a transient propargylic hydrazide species. Decomposition of this unstable hydrazide via an intermediate monoalkyldiazine
through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
Palladium-catalysed coupling reaction of allenic alcohols with aryl- and alkenylboronic acids
作者:Masahiro Yoshida、Takahiro Gotou、Masataka Ihara
DOI:10.1039/b402047b
日期:——
The direct coupling of aryl- and alkenylboronic acids with allenic alcohols has been achieved using a palladium catalyst to yield various substituted dienes and trienes in high yields.