矢车菊中倍半萜——4,9-二氧-红没药-2,7(14),10-三烯及其类似物的合成

Synthesis: of Sesquiterpene from: Centaurea Species-4,9-Dioxo-bisabol-2,7(14), 10-triene and Its Analogues

红没药烯及其含氧化合物是自然界中存在的一类单环倍半萜,它是利用单萜合成倍半萜的实例。1986年Jakupovic等报道从植物矢车菊中提取出新的倍半萜——4,9-二氧-红没药-2,7(14),10-三烯及它的异构化产物4,9-二氧-红没药-2,7 E,10-三烯。我们以(-)-香芹酮(1 a)和(+)-二氢香芹酮(1b)作原料合成了4,9-二氧-红没药-2,7(14),10-三烯(4 a),它的二氢类似物4,9-二氧-红没药-7(14),10-二烯(4b)和4,9-二氧-

Reactions of 10-chlorocarvone (2a) or 10-chlorodihydrocarvone (2b) with iso- pentenal or isopentanal in the presence of zinc dust yielded homoallylic alcohol (3a-c) with a bisabolene skeleton. 3a-c were Oxidized to 4,9-dioxo-bisabol-2,7(14), 10-triene(4a), 4, 9-dioxo-bisabol-7(14), 10-diene (4b) and 4,9-diexo-bisabo1-7(14)-ene(4c) respectively by chromium trioxide-pyridine complex. 4,9-Dioxo-bisabol-7 E, 10-diene (5b) was obtained from dihydrocarvone (1b) acetal ally1 lithium species and isopentenal via a sequence of reactions.