Chemoenzymatic Total Synthesis of the Proposed Structures of Putaminoxins B and D

J Nat Prod. 2017 May 26;80(5):1563-1574. doi: 10.1021/acs.jnatprod.7b00101. Epub 2017 Apr 26.

Abstract

Different enzymatic and nonenzymatic approaches were tested and compared to afford enantiopure homoallylic and allylic alcohols as building blocks in a total synthesis showcase. Thereby, highly enantioselective alcohol dehydrogenases and the P450 BM3 monooxygenase variant A74G L188Q were compared to classical asymmetric reagent-controlled allyl additions. Thus, the first total syntheses of the proposed structures for putaminoxins B/D and their respective enantiomers were accomplished. Detailed spectroscopic analysis of the newly synthesized compounds unraveled a discrepancy with respect to the reported structures of putaminoxins B/D. Furthermore, it was demonstrated that total synthesis is generally required for unequivocal assignment of configuration, because purely comparative NMR studies and judgment by analogy can lead to false predictions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alcohols / chemistry*
  • Catalysis
  • Lactones / chemical synthesis*
  • Lactones / chemistry
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Stereoisomerism

Substances

  • Alcohols
  • Lactones
  • putaminoxin B
  • putaminoxin D