Total synthesis and structural elucidation of (-)-maurenone.
[reaction: see text] The total synthesis of (2S,3S)-2,3-dihydro-6-[(1'S, 2'R)-2-hydroxy-1-methylbutyl]-3,5-dimethyl-2-[(1''S)-1-methylpropyl]-4H-pyran-4-one (3), the (-)enantiomer of the marine polypropionate, maurenone, was achieved in nine linear steps (13% overall yield) from (R)-2-benzylpentan-3-one ((R)-14) and (R)-2-benzoyloxypentan-3-one ((R)-15). Key fragments were synthesized using highly diastereoselective syn and anti boron aldol reactions and were coupled using a lithium-mediated aldol reaction. Trifluoroacetic acid-promoted cyclization/dehydration was then used to install the gamma-dihydropyrone ring. Eight isomers of one enantiomeric series were synthesized by coupling two ketones with each of four aldehydes. Comparison of the 13C NMR data for the eight isomers with that reported for maurenone established the relative stereochemistry of the natural product.
Crossman
Julia S
JS
School of Chemistry, Physics, and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
Perkins
Michael V
MV
D000447:Aldehydes / Q000138:chemical synthesis / Q000737:chemistry; D001688:Biological Products / Q000737:chemistry; D003500:Cyclization; D007536:Isomerism; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009930:Organic Chemicals / Q000138:chemical synthesis* / Q000737:chemistry; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry; D014867:Water / Q000737:chemistry
D000447:Aldehydes; D001688:Biological Products; D007659:Ketones; D009930:Organic Chemicals; D011753:Pyrones; C511843:maurenone; D014867:Water; D008094:Lithium