METHYL (.ALPHA.E,1'S,6'S,7'S,8'AS)-4-CYANO-6'-ETHYL-1,2',3,3',6',7',8',8'A-OCTAHYDRO-.ALPHA.-(METHOXYMETHYLENE)-3-OXOSPIRO(2H-INDOLE-2,1'(5'H)-INDOLIZINE)-7'-ACETATE
methyl (.alpha.e,1's,6's,7's,8'as)-4-cyano-6'-ethyl-1,2',3,3',6',7',8',8'a-octahydro-.alpha.-(methoxymethylene)-3-oxospiro(2h-indole-2,1'(5'h)-indolizine)-7'-acetate