The Povarov reaction of ethyl (18-carbomethoxyabieta-8,11,13-triene-12-imino)glyoxylate with electron-donating dienophiles
摘要:
Ethyl (18-carbomethoxyabieta-8,11,13-triene-12-imino)glyoxylate undergoes cyclization with ethyl vinyl ether or N-vinyl-pyrrolidone to 3-ethoxycarbonyl-5-isopropyl-9-methoxycarbonyl-9,12a-dimethyl-7,8,8a,9,10,11,12,12a-octahydronaphtho[1,2-f]-quinoline under BF3 center dot OEt2 catalysis; the corresponding reaction with cyclopentadiene proceeds with moderate diastereoselectivity at -20 degrees C.