177187-13-2Relevant academic research and scientific papers
Stereoselective construction of the dicyelopenta[a,d]cyclooctene core of the ceroplastin sesterterpenes by way of the anionic oxy-cope rearrangement
Paquette, Leo A.,Liang, Shaowo,Wang, Hui-Ling
, p. 3268 - 3279 (1996)
Bicyclo[3.2.1]oetanediones such as 9, which are readily available by double carbonylation of (1,3-cyclohexadiene)iron tricarbonyl complexes according to Eilbracht, are amenable to regiospecific methylenation under Wittig conditions. Reduction of 10 with copper hydride leads to 11, which can be resolved by application of Johnson's sulfoximine technology and oxidized to give the enantiopure antipodes of 10. Variously substituted cyclopentenyl anions undergo 1,2-addition to 10, providing carbinols which are capable of anionic oxy-Cope rearrangement via chair transition states. These structural reorganizations are fully stereocontrolled and lead directly to functionalized dicyclopenta[a,d]cyclooctenes. When 11 is treated analogously, only [1,3] sigmatropy is observed and inversion of stereochemistry at the migrating carbon prevails. Both processes exhibit impressive scaffolding powers and are characterized by brevity.
