enolates as nucleophiles with aromatic aldehydes chemoselectively proceeded in the presence of silyl triflate and 2,2′-bipyridyl to produce β-siloxy aldehydes, while the aliphaticaldehydes were completely recovered. The unprecedented chemoselectivities depend on the reactivities of the pyridinium-type intermediatesderivedfrom the aromatic and aliphaticaldehydes.
Room-Temperature, Acid-Catalyzed [2+2] Cycloadditions: Suppression of Side Reactions by using a Flow Microreactor System
作者:Kei Kurahashi、Yoshiji Takemoto、Kiyosei Takasu
DOI:10.1002/cssc.201100373
日期:2012.2.13
Added value: The [2+2] cycloaddition of silyl enolethers with α,β‐unsaturated esters, catalyzed by the superstrong acid triflic imide (Tf2NH), at roomtemperature in a flow microreactor system is reported. The micororeactor method achieves the [2+2] cycloaddition of unstable silyl enolethers and acrylates, which is unsuccessful in batch reactors, even at roomtemperature.
作者:Jinhua J. Song、Zhulin Tan、Jonathan T. Reeves、Daniel R. Fandrick、Nathan K. Yee、Chris H. Senanayake
DOI:10.1021/ol703025b
日期:2008.3.1
In the presence of a catalytic amount of NHC 3 (IAd, 0.1 to 5 mol %), a series of enolizable ketones as well as cyclohexanecarboxaldehyde were efficiently converted into the corresponding silyl enolethers at 23 degrees C in THF.
Chiral Allenes via Alkynylogous Mukaiyama Aldol Reaction
作者:Aurélien Tap、Aurélie Blond、Vijay N. Wakchaure、Benjamin List
DOI:10.1002/anie.201603649
日期:2016.7.25
development of a catalyticenantioselective alkynylogous Mukaiyamaaldolreaction. The reaction is catalyzed by a newly designed chiral disulfonimide and delivers chiral allenoates in high yields and with excellent regio‐, diastereo‐, and enantioselectivity. Our process tolerates a broad range of aldehydes in combination with diverse alkynyl‐substituted ketene acetals. The reaction products can be readily
Combined C–H Functionalization/Cope Rearrangement with Vinyl Ethers as a Surrogate for the Vinylogous Mukaiyama Aldol Reaction
作者:Yajing Lian、Huw M. L. Davies
DOI:10.1021/ja2051155
日期:2011.8.10
selectively undergo the combined C-H functionalization/Cope rearrangement reaction via an s-cis/boat transition state. With chiral dirhodium catalysts, products are generated in a highly diastereoselective and enantioselective fashion. This reaction can be considered as a surrogate to the traditional vinylogousMukaiyamaaldolreaction. Effective kinetic resolution has been achieved, leading to the recovery