Chemoenzymatic total syntheses of the linear triquinane-type natural products (+)-hirsutic acid and (−)-complicatic acid from toluene
摘要:
Total syntheses of title natural products, 1 and 2, have been achieved using the cis-1,2-dihydrocatechol 7 as starting material. Compound 7 is readily obtained in large quantity and enantiomerically pure form through the whole-cell biotransformation of toluene using the genetically engineered micro-organism Escherichia coli JM109 (pDTG601) that over-expresses the enzyme toluene dioxygenase (TDO). Three key chemical steps were employed in these syntheses, the first of which was a high-pressure- promoted Diels-Alder cycloaddition reaction between diene 8 and cyclopentenone to give adduct 9. The second key step was the photochemically promoted oxa-di-pi-methane rearrangement of the bicyclo[2.2.2] octenone derivative, 18, of 9 to give 20 while the third key step was the reductive cleavage of the last compound so as to afford the linear triquinane 22. Elaboration of compound 22 to targets 1 and 2 followed conventional and/or established procedures. Single-crystal X-ray analyses were carried out on compounds 10-13, 15, 18, 24, and 34. (c) 2007 Elsevier Ltd. All rights reserved.
The first asymmetric total synthesis of (+)-hirsutic acid has been accomplished in a highly stereocontrolled manner, including a novel method for the preparation of (1S, 5R, 6S)-6-hydroxy-cis-bicyclo[3.3.0]octan-3-one and a stereospecific Simmons-Smith reaction controlled by the participation of a relatively remote hydroxyl group.
A chirally directed totalsynthesis of (+)-hirsuticacid from 1,3-cyclooctadiene has been accomplished in a highly stereocontrolled manner.
由1,3-环辛二烯手性完全合成(+)-亚硫酸的酸已经以高度立体可控的方式完成。
Formal total synthesis of (±)-hirsutic acid C using the tandem Rh(I)-catalyzed [(5+2)+1] cycloaddition/aldol reaction
作者:Changxia Yuan、Lei Jiao、Zhi-Xiang Yu
DOI:10.1016/j.tetlet.2010.08.028
日期:2010.10
A concise formal total synthesis of the linear triquinane natural product (±)-hirsutic acid C has been achieved. This synthesis features a tandem Rh(I)-catalyzed [(5+2)+1] cycloaddition/aldol reaction as the key step to build the triquinaneskeleton.