Torihata Munefumi, Nakahata Takashi, Kuwahara Shigefumi
Laboratory of Applied Bioorganic Chemistry, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 981-8555, Japan.
Org Lett. 2007 Jun 21;9(13):2557-9. doi: 10.1021/ol070956f. Epub 2007 Jun 1.
The first enantioselective total synthesis of isishippuric acid B bearing a novel 4,5-seco-6-norquadrane skeleton was accomplished from (R)-citronellal with use of a Diels-Alder cycloaddition and an intramolecular Michael addition as the ring-forming steps. Comparison of the optical rotation of the synthetic material with that of the natural product confirmed the absolute configuration of isishippuric acid B to be 1R, 2R, 8R, and 11R.
以（R）-香茅醛为原料，通过狄尔斯-阿尔德环加成反应和分子内迈克尔加成反应作为成环步骤，首次完成了具有新型4,5-开环-6-降蒈烷骨架的异海罂粟酸B的对映选择性全合成。将合成产物的旋光性与天然产物的旋光性进行比较，证实异海罂粟酸B的绝对构型为1R、2R、8R和11R。
