Stereocontrolled synthesis of (±)-α-pinguisene and (±)-pinguisenol

Abstract

Total synthesis of (±)-α-pinguisene 1 and (±)-pinguisenol 2, employing an orthoester Claisen rearrangement and an intramolecular diazo ketone cyclopropanation reaction for the stereospecific construction of vicinal quaternary carbon atoms, is described.

References

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2. So far there is only one approach reported for α-pinguisene 1 pinguisenol 2, see: D. Schinzer, K. Ringe, P. G. Jones and D. Döring, Tetrahedron Lett., 1995, 36, 4051; D. Schinzer and K. Ringe, Tetrahedron, 1996, 52, 7475 The authors referred to α-pinguisene as β-pinguisene. For the synthesis of pinguisone and its derivatives see, S. Bernasconi, P. Gariboldi, G. Jommi, S. Montanari and M. Sisti, J. Chem. Soc., Perkin Trans. 1, 1981, 2394; T. Uyehara, Y. Kabasawa and T. Kato, Bull. Chem. Soc. Jpn., 1986, 59, 2521; R. Baker, D. L. Selwood, C. J. Swain, N. M. H. Webster and J. Hirshfield, J. Chem. Soc., Perkin Trans. 1, 1988, 471 and references cited therein.
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4. It is worth noting that as per the molecular mechanics calculations, unlike in the diketone 16, in 1,2,6,7-tetramethylbicyclo[4.3.0]nonan-3,8-diones the 1β,2α,6β,7α-isomer is more stable than the 1β,2β,6β,7β-isomer.