Phase Transfer Catalysis. Part-III : Studies of a Few Michael Reactions of Synthetic Utility under Phase Transfer Catalysis

Department of Chemistry, Indian Institute of Technology, Kharagpur-721 302

A few Michael condensations with ethyl cyanoacetate, diethyl malonate, benzyl cyanide, o-methylbenzyl cyanide and benzyl methyl ketone as donors and 4-methylpent-3- en-2-one (mesityl oxide), ethyl acrylate, methyl crotonate and methyl α, α-dimethylacry­late as acceptors under phase transfer catalysis (in presence of benzyltriethylammonium chloride and K₂CO₃) have been carried out. The method is superior to conventional base-catalysed Michael reaction with regards to yields which are often excellent. Substrates like ethyl phenethylcyanoacetate and 3,4-dihydro-1-(2H)-napbthalenone ( 1-tetralone ) which are resistant to Michael addition also undergo condensation with mesityl oxide, although in low yield, under phase transfer catalysis. Some of the products are useful synthetic intermediates.