Total synthesis, structural revision and biological evaluation of γ-elemene-type sesquiterpenes

Org Biomol Chem. 2018 Oct 31;16(42):7843-7850. doi: 10.1039/c8ob02005a.

Abstract

Total synthesis and absolute configuration confirmation of γ-elemene-type sesquiterpenes, which possess vast potential for biological activities, was investigated based on a convergent synthetic strategy. A key intermediate with all functional groups of this family of natural products was accessed by an intermolecular aldol reaction and then an acetylation of a known ketone (12) derived from commercially available verbenone. The versatile intermediate can be easily transformed into structurally different γ-elemene-type sesquiterpenes based on control of base-promoted cyclization manipulation in different solvents. The utility of this robust approach is illustrated by the first syntheses of elema-1,3,7(11),8-tetraen-8,12-lactam (4') and 8β-methoxy-isogermafurenolide (6a), as well as the syntheses of elem-1,3,7,8-tetraen-8,12-olide (3) and hydroxyisogermafurenolide (5) in only 6 or 7 steps. In addition, the structure of the reported 5βH-elem-1,3,7,8-tetraen-8,12-olide (1) was revised as elem-1,3,7,8-tetraen-8,12-olide (3) by comparison of their identified datum, and the absolute configuration of elema-1,3,7(11),8-tetraen-8,12-lactam was confirmed as 4'. Furthermore, the inhibitory effect of all synthesized natural compounds and their natural analogues on cancer cell proliferation was evaluated. Among them compounds 3, 4 and 4' were found to possess potent inhibitory activity against Kasumi-1 and Pfeiffer. Meanwhile, preliminary structure-activity relationships for these compounds are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Antineoplastic Agents* / chemical synthesis
  • Antineoplastic Agents* / chemistry
  • Bicyclic Monoterpenes
  • Cell Line, Tumor
  • Cyclization
  • Humans
  • Lymphoma / drug therapy
  • Oxidation-Reduction
  • Sesquiterpenes* / chemical synthesis
  • Sesquiterpenes* / chemistry
  • Structure-Activity Relationship
  • Terpenes / chemistry

Substances

  • Antineoplastic Agents
  • Bicyclic Monoterpenes
  • Sesquiterpenes
  • Terpenes
  • elemene
  • verbenone