A synthesis of highly substituted and sterically congested bicyclo[4.3.1]decenes, a structure embedded in the core 4,7,6-tricyclic system of natural caryolanes, was successfully achieved via a ring-closing metathesis (RCM) reaction of syn-1,3-diene substituted cyclohexanols. The construction of the diene substrates, starting from 4-acetoxy-3-methyl-2-cyclohexen-1-one, employed diastereoselective copper-mediated conjugate addition and Grignard reactions. An X-ray crystal structure determination of a key synthetic intermediate confirmed the relative stereochemistry of the RCM bicyclic product.
Goldring, W. P. D., & Paden, W. T. (2011). A ring-closing metathesis approach to the bicyclo 4.3.1 decane core of caryolanes. Tetrahedron Letters, 52(8), 859-862. https://doi.org/10.1016/j.tetlet.2010.11.138