Vinylic carbanions in synthesis. Novel syntheses of iso-gregatin B, iso-aspertetronin A and related O-methyl tetronic acids
作者:Nicholas G. Clemo、Gerald Pattenden
DOI:10.1016/s0040-4039(00)86897-5
日期:1982.1
Reaction between the octadienone (8) and the vinylic carbanion (6) derived from (5) leads, in one step, to the O-methyl tetronic acid (9). Metallation of (9), followed by treatment of the resulting α-vinylic carbanion with methyl acetate and with methyl -butenoate then gives the acylated O-methyl tetronic acids (12) and (14) respectively which are shown to be enol ether isomers of the natural products
辛二烯酮(8)与衍生自(5)的乙烯基碳负离子(6)之间的反应一步就生成了O-甲基四氢代酸(9)。将(9)金属化,然后用乙酸甲酯和丁烯酸甲酯处理所得的α-乙烯基碳负离子,然后分别得到酰化的O-甲基四氢代酸(12)和(14),它们被证明是烯醇式的烯醇醚异构体。天然产物凝集素B和阿斯替考林A在西藏发现。和。