Stereoselective synthesis of alicyclic ketones: A hydrogen borrowing approach
A highly diastereoselective annulation strategy for the synthesis of alicyclic ketones from diols and pentamethylacetophenone is described. This process is mediated by a commercially available iridium(III) catalyst, and provides efficient access to a wide range of cyclopentane and cyclohexane products with high levels of stereoselectivity. The origins of diastereoselectivity in the annulation reaction have been explored by a series of control experiments, which provides an explanation for how each stereocentre around the newly forged ring is controlled.
Armstrong, Roly J.,Akhtar, Wasim M.,Frost, James R.,Christensen, Kirsten E.,Stevenson, Neil G.,Donohoe, Timothy J.
supporting information
(2019/11/13)
Stereoselective Synthesis of Cyclohexanes via an Iridium Catalyzed (5 + 1) Annulation Strategy
An iridium catalyzed method for the synthesis of functionalized cyclohexanes from methyl ketones and 1,5-diols is described. This process operates by two sequential hydrogen borrowing reactions, providing direct access to multisubstituted cyclic products with high levels of stereocontrol. This methodology represents a novel (5 + 1) strategy for the stereoselective construction of the cyclohexane core.
Akhtar, Wasim M.,Armstrong, Roly J.,Frost, James R.,Stevenson, Neil G.,Donohoe, Timothy J.
p. 11916 - 11920
(2018/09/27)
Asymmetric conjugate addition of malonate to α,β-unsaturated ketones in water using a perfluoroalkanesulfonamide organocatalyst
Perfluoroalkanesulfonamide organocatalyst 7 efficiently promotes asymmetric Michael additions of malonates to enones in cyclohexane or water to produce the corresponding addition products with excellent yields and with up to 99% ee.
Asymmetric conjugate addition of malonates to enones using Perfluorobutanesulfonamide organocatalyst
Perfluorobutanesulfonamide organocatalyst 4 efficiently promotes asymmetric conjugate additions of malonates to α,β-unsaturated ketones to afford the corresponding adducts with excellent enantioselectivities (up to 99% ee).
Simple chiral sulfonamide primary amine catalysed highly enantioselective Michael addition of malonates to enones
A chiral sulfonamide primary amine-organocatalysed, highly enantioselective Michael addition of malonates to enones has been developed. This reaction afforded the corresponding products in excellent yields (up to 99%) and excellent enantioselectivity (up
Luo, Chunhua,Jin, Yu,Du, Da-Ming
experimental part
p. 4116 - 4123
(2012/06/15)
Organocatalyzed highly enantioselective michael additions of malonates to enones by using novel primary-secondary diamine catalysts
A novel primary-secondary diamine catalyst readily available from primary amino acids in three steps for the highly enantioselective Michael additions of malonates to α,β-unsaturated ketones was reported. The Michael reaction of dimethyl malonate with benzylideneacetone was selected as a model reaction for catalyst evaluation. The length of the alkyl chain is found to influence the catalytic abilities of the catalysts and the n-propylated catalyst gave the highest yield and ee value. The addition of a series of malonates to enone performed under the optimized conditions is found to be sensitive to the steric hinderance on the malonates. Heterocyclic furan enone is found to perform well to give the desired product in 92% yield and 99% ee, while no decrease in yield and ee value is observed for sterically hindered enone.
Yang, Ying-Quan,Zhao, Gang
supporting information; experimental part
p. 10888 - 10891
(2009/10/02)
A general organocatalytic enantioselective malonate addition to α,β-unsaturated enones
A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to α,β-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic e
Wascholowski, Veit,Knudsen, Kristian Rahbek,Mitchell, Claire E. T.,Ley, Steven V.
experimental part
p. 6155 - 6165
(2009/05/27)
Asymmetric organocatalytic conjugate addition of malonates to enones using a proline tetrazole catalyst
5-Pyrrolidin-2-yltetrazole performs as a useful organocatalyst for the asymmetric addition of malonates to a range of enones, with good to excellent enantioselectivities. The Royal Society of Chemistry 2006.
Knudsen, Kristian Rahbek,Mitchell, Claire E. T.,Ley, Steven V.
p. 66 - 68
(2008/02/06)
Highly enantioselective organocatalytic conjugate addition of malonates to acyclic α,β-unsaturated enones
An imidazolidine easily prepared from phenylalanine is the catalyst for the highly enantioselective Michael addition shown. A great diversity of α,β-unsaturated enones was transformed with excellent enantioselectivities. The scope of the reaction is furth
Halland, Nis,Aburel, Pompiliu S.,Jorgensen, Karl Anker
p. 661 - 665
(2007/10/03)
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