Synthesis of Seven-Membered Carbocyclic Rings via a Microwave-Assisted Tandem Oxyanionic 5-<i>exo</i> <i>dig</i> Cyclization−Claisen Rearrangement Process

2007-08-17T00:00:00Z (GMT) by Xin Li Robert E. Kyne Timo V. Ovaska
Appropriately substituted 1-alkenyl-4-pentyn-1-ol systems, readily prepared from simple starting materials, serve as useful precursors to a number of substituted cyclohept-4-enone derivatives via a microwave-assisted tandem oxyanionic 5-<i>exo</i> cyclization/Claisen rearrangement sequence. The reactions involving terminally substituted 4-pentyn-1-ols were found to be highly stereoselective, with the α and β groups in the final product showing a strong preference for the <i>trans</i> orientation.