ON THE BAYLIS-HILLMAN REACTION OF ACRYLATE, ACRYLONITRILE, AND ACROLEIN WITH SOME NONENOLIZABLE ALPHA-DICARBONYL COMPOUNDS - SYNTHESIS OF PHYTOTOXIC BIPOLAROXIN MODELS

The Baylis-Hillman reaction of acrylonitrile, methyl acrylate, and acr olein with several cyclic alpha-dicarbonyl compounds was investigated. Whereas acrylonitrile reacted with most of these ketones, giving good yields of the expected 1'-cyanovinyl carbinols, the more sterically d emanding methyl acrylate failed to undergo the reaction. Attempted Bay lis-Hillman reaction of acrolein with the 1,2-dicarbonyl substrates us ually resulted in polymers but, in two cases, the desired alpha-substi tuted acroleins were obtained. An alternative route to such compounds was developed, employing a Grignard - allylic oxidation sequence. In b ioassays, some of the products, embodying the functionality believed r esponsible for the phytotoxicity of the sesquiterpene bipolaroxin, inh ibited germination of lettuce seeds. This activity diminished with tim e.