Unexpected Alkene Isomerization during Iterative Cross-Coupling To Form Hindered, Electron-Deficient Trienes

• DOI: 10.1021/acs.orglett.8b00809
• Publication Date: 2018-05-21T11:36:37Z
• Authors: Abigail Feceu; Lauren E. Sangster; David B. C. Martin
• Keywords: Alkene

An iterative cross-coupling approach to conjugated trienes was explored as part of a planned stereoselective synthesis bicyclic terpenes. Using bifunctional bromoboronate building block, sequential Suzuki coupling reactions were employed provide trienone target containing tetrasubstituted alkene. During the final step, an unexpected alkene isomerization observed give less hindered trans products. Examination different substrates determined that conjugation ketone withdrawing group responsible for isomerization, rather than steric hindrance