Studies on Steroidal Plant-Growth :Regulators: A New Synthesis of Brassinosteroids
作者:Wei-Shan Zhou、Yi-Pine Zhou、Biao Jiang
DOI:10.1055/s-1989-27273
日期:——
Two brassinosteroids (stereoisomers of brassinolide), (22R,23R,24R)-2α,3α,22,23-tetrahydroxy-B-homo-7-oxa-5α-ergostan-6-one (2) and (22S,23S,24R)-2α,3α,22, 23-tetrahydroxy-B-homo-7-oxa-5α-ergostan-6-one (3), were synthesized from ergosterol in eight steps in ca. 30% overall yield. The key step is the highly regioselective formation of the 7-oxalactone ring by oxidation of an enol silyl ether with 3-chloroperoxybenzoic acid.
两种芸苔素(芸苔素的立体异构体),(22R,23R,24R)-2α,3α,22,23-四羟基-B-高-7-氧杂-5α-麦角甾烷-6-酮(2)和(22S,23S,24R)-2α,3α,22,23-四羟基-B-高-7-氧杂-5α-麦角甾烷-6-酮(3),是从麦角甾醇通过八个步骤合成的,总产率约为30%。关键步骤是通过3-氯过氧苯甲酸氧化烯醇硅醚,高度选择性地形成7-氧代内酯环。