β‐Diazocarbonyl Compounds: Synthesis and their Rh(II)‐Catalyzed 1,3 C−H Insertions
作者:Liyin Jiang、Zhaofeng Wang、Melanie Armstrong、Marcos G. Suero
DOI:10.1002/anie.202015077
日期:2021.3.8
of ketone silyl enol ethers with diazomethyl‐substituted hypervalent iodine reagents that gives access to unusual β‐diazocarbonyl compounds. The potential of this unexplored class of diazo compounds for the development of new reactions was demonstrated by the discovery of a rare Rh‐catalyzed intramolecular 1,3 C−H carbene insertion that led to complex cyclopropanes with excellent stereocontrol.
A ruthenium-catalyzed [1,2]-Brook rearrangement involved dominosequence is presented to prepare highly functionalized silyloxy indenes with atomic- and step-economy. This domino reaction is triggered by acylsilane-directed C–H activation, and the aldehyde controlled the subsequent enol cyclization/Brook Rearrangement other than β–H elimination. The protocol tolerates a broad substitution pattern,
Development of N,N-bis(perfluoroalkanesulfonyl)squaramides as new strong Brønsted acids and their application to organic reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tet.2010.03.120
日期:2010.6
l groups have been developed and applied to several organic reactions. These squaramides are bench-stable and exhibit much higher reactivities in several organic reactions than squaric acid itself. N,N-Bis(trifluoromethanesulfonyl)squaramide 2a was applied to the Mukaiyama aldol reaction and Mukaiyama Michael reaction. Mechanistic studies revealed that the Brønsted acid might be the predominant catalyst
The reaction of (chloromethylene)dimethylammonium chloride (generated in situ from oxalyl chloride and DMF) with α-substituted ketones in CH2Cl2, followed by workup with aqueous NaHCO3, gave β-keto aldehydes containing an α-quaternary centre (8-88% yield).