Esters and thiolesters of unsaturated acids

A compound of the following formula (A):

• ##STR3## wherein:
• R is oxygen, sulfur, methylene or carbonyl;
• R' is hydrogen, fluoro, bromo, chloro, trifluoromethyl, methyl, methoxy or methylthio;
• each of R.sup.2 and R.sup.3 is independently selected from hydrogen, chloro, fluoro, bromo, lower alkyl, lower alkenyl, lower alkoxy, cycloalkalkyl, and lower haloalkyl;
• R.sup.4 is lower alkyl of 2 to 5 carbon atoms, lower alkenyl of 2 to 5 carbon atoms, or cyano;
• R.sup.5 is hydrogen, cyano, ethynyl or methyl;
• W is oxygen or sulfur;
• t is zero, one, two, three or four;
• Y is independently selected from hydrogen, lower alkyl, lower haloalkyl, lower alkoxy, lower alkylthio, lower alkylcarbonyl, lower alkoxycarbonyl, lower acyloxy, halogen, cyano, nitro, and lower haloalkylthio;
• and
• Z is independently selected from the values of Y, cycloalkyl, and lower haloalkoxy;
• or
• Y and Z form a methylenedioxy group.