rac. (Z)-1,3,4,5-Tetrahydro-3-methoxycarbonylmethyl-4,4,3',4'-tetramethyl-5-oxo-2,2'-pyrromethen-5'-carbonsaeure-tert-butylester 、
(Z)-4-Ethyl-1,3-dimethyl-5-(3,4-dimethyl-5-formyl-2-pyrrolyl-methylen)-3-pyrrolin-2-on 以50%的产率得到rac. (Z,Z,Z)-17-Ethyl-1,19-dioxo-3-methoxycarbonylmethyl-2,2,7,8,12,13,18,24-octamethyl-1,2,3,19,23,24-hexahydro-21H-bilin