Triflimide: An Overlooked High-Performance Catalyst of the Mukaiyama Aldol Reaction of Silyl Ketene Acetals with Ketones
作者:Han Yong Bae、Benjamin List
DOI:10.1002/chem.201803142
日期:2018.9.18
The Mukaiyamaaldolreaction is a widely applied carbon–carbon bond forming reaction. However, despite numerous well‐established methods using aldehydes as acceptors, only few examples exist with ketones. Here we report a highly practical catalytic approach to this transformation, namely, the triflimide catalyzedMukaiyamaaldolreaction of silyl ketene acetals with ketones. This method exhibits a
A novel [3+2] type reaction of 2,2-dialkoxycyclopropanecarboxylic esters with ketene silyl acetals, mediated by titanium(IV) chloride, afforded 3-alkoxy-2- (or -3-) cyclopentenone derivatives.
Selective Aryne Formation via Grob Fragmentation from the [2+2] Cycloadducts of 3-Triflyloxyarynes
作者:Jiarong Shi、Hai Xu、Dachuan Qiu、Jia He、Yang Li
DOI:10.1021/jacs.6b12161
日期:2017.1.18
chemoselective ring-opening protocol of the formal [2+2] cycloadducts of 3-triflyloxyarynes was developed to generate 2,3-aryne intermediate via Grob fragmentation. A variety of 1,3-di- and 1,2,3-trisubstituted arenes could be readily accessed through this [2+2] cycloaddition-2,3-aryne formation sequence. The regioselectivity in these transformations originates from the steric repulsion of the aliphatic chain
Lewis acid catalysis in a supercritical carbon dioxide (scCO2)-poly(ethylene glycol) derivatives (PEGs) system: remarkable effect of PEGS as additives on reactivity of Ln(OTf)3-catalyzed Mannich and aldol reactions in scCO2
作者:Ichiro Komoto、Shū Kobayashi
DOI:10.1039/b106437c
日期:——
Use of poly(ethylene glycol) derivatives (PEGs) as additives
in supercritical carbon dioxide (scCO2) was found to be
effective for Mannich and aldol reactions of silyl enolates with aldehydes
and imines, and formation of emulsions was observed in these systems.
Site‐Selective C–C Cleavage of Benzocyclobutenones Enabled by a Blocking Strategy Using Nickel Catalysis
作者:Jing‐Hong Guo、Yu Liu、Xin‐Cheng Lin、Tian‐Mu Tang、Bi‐Qin Wang、Ping Hu、Ke‐Qing Zhao、Feijie Song、Zhang‐Jie Shi
DOI:10.1002/anie.202106709
日期:2021.8.23
Controlling the chemo- and regioselectivity of transition-metal-catalyzed C−C activation remains a great challenge. The transformations of benzocyclobutenones (BCBs) usually involve the cleavage of C1−C2 bond. In this work, an unprecedented highly selective cleavage of C1−C8 bond with the insertion of alkynes is achieved by using blocking strategy via Ni catalysis, providing an efficient method for