Mild and efficient catalytic method for α-trimethylsilyl ketones

Abstract

A mild, efficient and convenient method for the synthesis of α-silyl ketones from corresponding aldehydes and trimethylsilyldiazomethane in the presence of a catalytic amount of indium(III) chloride has been developed.

Metal-Catalyzed Rearrangement of Cyclopropenes to Allenes

“…The relatively facile preparation and better reaction profiles of non-C3-substituted silylated cyclopropenes relative to other cyclopropenes prompted us to choose them as the substrate platform for further exploration of the rearrangement of cyclopropenes to allenes. These non-C3-substituted cyclopropenes were prepared by the C–Si bond insertion method recently developed in our laboratory . Herein we describe the first efficient metal-catalyzed rearrangement of silylated cyclopropenes to the corresponding allenes.…”

“…Relying on the reported method, we prepared a variety of silylated cyclopropenes 9a – j and examined their conversion to the corresponding allenes (Table ). The simple alkyl chain-substituted cyclopropene 9a afforded allene 10a in excellent yield (entry 1), but the reaction of 3-butenyl-substituted cis and trans isomers of 9b was not satisfactory (entry 2) .…”

An Alkylidene Carbene C–H Activation Approach toward the Enantioselective Syntheses of Spirolactams: Application to the Synthesis of (−)-Adalinine

“…The resulting brown colored solution was stirred at −78 °C for 30 min, and then the reaction temperature was gradually allowed to warm to 0 °C over a period of 1 h. Under these conditions, the spirolactam 20a was isolated in 40% yield in addition to two unexpected ketones 21 (19%) and 22 (8%). The formation of the homologated ketones such as 21 and 22 is not usually observed under LTDM reaction conditions, but is more commonly encountered in Lewis acid catalyzed reactions of carbonyl compounds with TMSDM …”

Gold(i)-catalyzed homologation of aryl aldehydes with trimethylsilyldiazomethane

“…Previous homologation reactions of aldehydes with TMSCHN 2 catalyzed by Lewis acids such as BF 3 or In 3+ selectively generate α-silyl ketones. 24 The current methodology could be a useful method that complements the previous examples of homologation reactions of aryl aldehydes.…”