- Copper(II)-Catalyzed Tandem Decarboxylative Michael/Aldol Reactions Leading to the Formation of Functionalized Cyclohexenones
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This work describes the development of a new single-pot copper(II)-catalyzed decarboxylative Michael reaction between β-keto acids and enones, followed by in situ aldolization, which results in highly functionalized chiral and achiral cyclohexenones. The achiral version of this Robinson annulation features a hitherto unprecedented Michael reaction of β-keto acids with sterically hindered β,β′-substituted enones and provides access to all carbon quaternary stereocenter-containing cyclohexenones (11 examples, 43-83% yield). In addition, an asymmetric chiral bis(oxazoline) copper(II)-catalyzed single-pot Robinson annulation has been devised for preparing chiral cyclohexenones, including some products that contain vicinal stereocenters (5 examples, 65-85% yield, 84-94% ee). This latter protocol has been successfully applied to the enantioselective formation of the oxygenated 10-nor-steroid core from readily available starting materials.
- Lee, Jeonghyo,Wang, Sibin,Callahan, Miranda,Nagorny, Pavel
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supporting information
p. 2067 - 2070
(2018/04/16)
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- Highly efficient synthesis of chiral aromatic ketones: Via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones
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A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstituted enones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions (>99%) with excellent enantioselectivities (up to 96% ee).
- Zhang, Tao,Jiang, Jun,Yao, Lin,Geng, Huiling,Zhang, Xumu
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supporting information
p. 9258 - 9261
(2017/08/22)
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- Vinyl Weinreb amides: A versatile alternative to vinyl ketone substrates for the Heck arylation
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This paper describes the use of unsaturated Weinreb amides as excellent substrates for the Heck reaction. Subsequent derivatization of the products with organometallic reagents allowed access to a variety of substituted vinyl ketones that could not have been prepared directly via Heck reaction on unsaturated ketone precursors.
- Baker, David B.,Gallagher, Peter T.,Donohoe, Timothy J.
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p. 3690 - 3697
(2013/05/08)
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- Highly enantioselective asymmetric hydrogenation of (E)-β,β- disubstituted α,β-unsaturated Weinreb amides catalyzed by Ir(i) complexes of SpinPhox ligands
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The Ir(i) complexes of chiral spiro phosphino-oxazoline ligands (SpinPhox) have demonstrated good to excellent enantioselectivity in the asymmetric hydrogenation (AH) of a variety of (E)-β,β-disubstituted α,β-unsaturated N-methoxy-N-methylamides, affording the corresponding optically active Weinreb amides with up to 97% ee.
- Shang, Jian,Han, Zhaobin,Li, Yang,Wang, Zheng,Ding, Kuiling
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p. 5172 - 5174
(2012/06/18)
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