Carbonyls as Latent Alkyl Carbanions for Conjugate Additions
作者:Xi-Jie Dai、Haining Wang、Chao-Jun Li
DOI:10.1002/anie.201700059
日期:2017.5.22
Conjugateaddition of carbon nucleophiles to electron-deficient olefins is one of the most powerful methods for forming carbon–carbon bonds. Despite great achievements in controlling the selectivity, variation of the carbon nucleophiles remains largely underexplored, with this approach relying mostly on organometallic reagents. Herein, we report that naturally abundant carbonyls can act as latent carbon
[reaction: see text] Bicyclo[4.3.0]nonanes (hydrindanes) and bicyclo[3.3.0]octanes (octahydropentalenes) are easily synthesized by palladium-catalyzed cycloalkenylations. Additionally, benzo-fused bicyclo[3.3.0]octanes are prepared for the first time through intramolecular coupling between silyl enol ethers and aromatic rings in the presence of catalytic palladium acetate.
Oxy-Allyl Cation Catalysis: An Enantioselective Electrophilic Activation Mode
作者:Chun Liu、E. Zachary Oblak、Mark N. Vander Wal、Andrew K. Dilger、Danielle K. Almstead、David W. C. MacMillan
DOI:10.1021/jacs.5b13041
日期:2016.2.24
enantioselective conversion of racemic α-tosyloxy ketones to optically enriched α-indolic carbonyls has been accomplished using a new amino alcohol catalyst in the presence of electron-rich indole nucleophiles. Kineticstudies reveal that the rate-determining step in this S(N)1 pathway is the catalyst-mediated α-tosyloxy ketone deprotonation step to form an enantiodiscriminant oxy-allyl cation prior to
Hydride reduction of alpha, beta-unsaturated carbonyl compounds using chiral organic catalysts
申请人:MacMillan David
公开号:US20060161024A1
公开(公告)日:2006-07-20
Nonmetallic, chiral organic catalysts are used to catalyze the 1,4-hydride reduction of an α,β-unsaturated carbonyl compound. The α,β-unsaturated carbonyl compound may be an aldehyde or cyclic ketone, and the hydride donor may be a dihydropyridine. The reaction is enantioselective, and proceeds with a variety of hydride donors, catalysts, and substrates. The invention also provides compositions effective in carrying out the 1,4-hydride addition of α,β-unsaturated carbonyl compounds.
Asymmetric 1,4-reductions of and 1,4-additions to enoates and related systems
申请人:Massachusetts Institute of Technology
公开号:US06465664B1
公开(公告)日:2002-10-15
One aspect of the present invention relates to methods for the transition-metal-catalyzed asymmetric 1,4-addition of a nucleophile, e.g., hydride, to cyclic and acyclic enoates and enones. In certain embodiments of the methods of the present invention, the transition metal catalyst consists essentially of copper and an asymmetric bidentate bisphosphine ligand.