The bicyclobutylidene to bicyclooctene rearrangement: Formal syntheses of (±)-ceratopicanol and (±)-hirsutene
作者:Thorsten Anger、Onno Graalmann、Heike Schröder、Ralf Gerke、Uta Kaiser、Lutz Fitjer、Mathias Noltemeyer
DOI:10.1016/s0040-4020(98)00635-8
日期:1998.9
The bicyclobutylidenes 2 and 5 have been rearranged to the bicyclooctenes 3 and 6, respectively, and further transformed to the tricyclic ketones 16 and 21, respectively, as known precursors of (±)-ceratopicanol (4) and (±)-hirsutene (7). For the cyclopentane annelation, a [3+2]cycloaddition with cyclopropane-1,1-dicarboxylic acid ester, followed by an alkaline hydrolysis and an oxidative decarboxylation
双环丁烯2和5已分别重排为双环辛烯3和6,并分别进一步转变为三环酮16和21,作为(±)-二十碳五烯醇(4)和(±)-多酚(7)的已知前体)。对于环戊烷脱环,使用与环丙烷-1,1-二羧酸酯进行的[3 + 2]环加成,然后进行碱水解和所形成的二酸的氧化脱羧(3-8-14-16,6-18 -20-21)。环加合物9,二酸15和酮17的结构接下来是对二甲苯磺酸酯13的X射线分析,其本身是通过还原和甲苯磺酸化获得的(9-12-13)。16和21的新合成代表4和7的短项。