The Reaction of Ketones with Diazomethane

Transition‐Metal‐Catalyzed Utilization of Methanol as a C1 Source in Organic Synthesis

“…Them ethylation of ketones is conventionally performed using diazomethane or methyl iodide, [14,15] which are toxic and/or explosive materials. [16] However,t he use of hydrogen transfer approaches with methanol constitutes ac onvenient method that has been applied to the regioselective methylation of CÀHb onds in ketones.G enerally,f or this methylation, homogeneous catalysts based on rhodium, iridium, and ruthenium have mainly been employed.…”

Grevellin Analogs with Affinity to theN-Methyl-D-aspartate (Glycine Site) Receptor, a Novel Lead Structure

“…House reported [13] that ketones and diazomethane gave the corresponding epoxides beside the homologous ketones and that the formation of the oxides was suppressed in the presence of boron trifluoride. It was concluded that this was due to Lewis acid catalyzed rearrangement of the initially formed epoxides.…”

2,3-Butanedione

“…with dihydrazino thiophosphites in a 1:1 ratio forms thiophosphatetraazacycloheptadienes (eq 9),9 whereas stirring with tris(trimethylsilyl) phosphite in benzene at rt furnishes the 3-trimethylsiloxy-2-butene-2-[bis(trimethylsilyl)] phosphate (eq 10).Reaction with Wittig Reagents. 2,3-Butanedione (1) undergoes the Wittig reaction with propylenetriphenylphosphorane to furnish a mixture of cis-and trans-3-methyl-3-hexen-2-ones in a 45:55 ratio (eq 11),11 whereas stirring ((1) with Diazomethane in ether containing excess methanol or 1 mol of Boron Trifluoride provides 2methyl-1-epoxybutan-3-one (eq 13),13 and with Diphenyldiazomethane furnishes 2-methyl-Condensation with Dimethyl 1,3-Acetonedicarboxylate.The dione (1) undergoes the Weiss-Cook process with Dimethyl 1,3-Acetonedicarboxylate to form tetramethyl 1catalyzed reaction of (1) with cis-1,2-cyclohexanediol forms normal mono-and diacetals, whereas stirring with transcyclohexanediol provides a different bisacetal, represented in eq 17.…”