Application of the Nickel-Mediated Neopentyl Coupling in the Total Synthesis of the Marine Natural Product Arenarol
作者:Anthony T. Watson、Kwangyong Park、David F. Wiemer、William J. Scott
DOI:10.1021/jo00121a030
日期:1995.8
Racemic arenarol (1) has been synthesized from the known decalin 5 beta-carbethoxy-1,1-(1,2-ethylenedioxy)-5 alpha,8a beta-dimethyl-1,2,3,5,6,7,8,8a-octahydro-6-oxonaphthalene (9) via a short, efficient, and highly stereocontrolled sequence. Key steps in this synthesis are the directed hydrogenation of an unsaturated neopentyl alcohol to provide stereocontrolled formation of the two adjacent tertiary centers and subsequent elaboration of the arenarol skeleton via a nickel-mediated coupling of the corresponding neopentyl iodide. This sequence demonstrates the value of nickel-mediated cross-coupling reactions for carbon-carbon bond formation at neopentyl centers.
Studies toward the synthesis of popolohuanone E: Synthesis of natural (+)-arenarol related to the proposed biogenetic precursor of popolohuanone E
decalin segment 6 required for the totalsynthesis of popolohuanone E (1) was efficiently synthesized starting from the enantiomericallypure (−)-Wieland-Miescher ketone derivative 9; the method features ortho ester Claisen rearrangement of 15 and Ir-catalyzed hydrogenation of 17 (Scheme 2). Furthermore, by employing 6 as the key decalin segment, the first totalsynthesis of natural (+)-arenarol (2) related
A novel marine natural product, (+)-aureol (1), was efficiently synthesized starting from the cis-fused decalin derivative 4. The synthetic method features borontrifluoride etherate-promoted rearrangement/cyclization reaction of (+)-arenarol (2) to form (+)-aureol (1) with complete stereoselectivity in high yield. (+)-Arenarol (2) was prepared in an alternative and more efficient manner employing