Synthesis of γ-butyrolactone fused cyclooctene

ABSTRACT

The expeditious route for the synthesis of γ-butyrolactone fused cyclooctene starting from the γ-butyrolactone fused cyclopentane through bicyclo[4.2.1]nonan-9-one is reported. Retro-Dieckmann’s condensation of bicyclo[4.2.1]nonan-9-one in presence of sodium methoxide and methanol furnished γ-butyrolactone fused cyclooctene in good yield. Surprisingly, the stereochemistry of ring-junction of γ-butyrolactone fused cyclooctene is different from the γ-butyrolactone fused cyclopentane, and the position of new ester group, which were confirmed unambiguously by X-ray analysis.

GRAPHICAL ABSTRACT

KEYWORDS:

• γ-Butyrolactone fused cyclooctene
• γ-lactone fused cyclopentane
• bicyclo[4.2.1]nonan-9-one
• retro-Dieckmann’s condensation
• ring closing metathesis

Acknowledgments

The authors thank the Department of Science and Technology (DST), New Delhi, for financial assistance. G. H. M. Rao thanks Dr. Ram, President of AAIMS, Jamaica.

Supporting information

Supporting information contains materials and methods, synthetic procedures and analytical data of 1, 3 and 4, ¹H and ¹³C NMR spectra of compounds 3, 4 and 5, and X-ray crystal data of compound 5 associated with this article can be found. Crystallographic data (excluding structure factors) for the structure 5 in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC 1561599.