Total synthesis of furanocembranolides. 3. A concise convergent route to acerosolide
                                
                                    
                                        作者:Leo A. Paquette、Peter C. Astles                                    
                                    
                                        DOI:10.1021/jo00053a031
                                    
                                    
                                        日期:1993.1
                                    
                                    The first synthesis of a 14-membered furanocembranolide has been achieved. The target molecule, acerosolide, contains two stereogenic cetners whose relative and absolute configuration have not previously been assigned. MM2 calculations performed during the course of the present work suggest their configuration to be 1(S*),10(R*). The synthesis began by SnCl2-promoted condensation of allylstannane 6 to aldehyde 7 so as to achieve regioreversed condensation and formation of the extended allylic alcohol 9. Acid-catalyzed lactonization and 2-fold oxidation via the bis-selenide gave butenolide 11 and subsequently the derived bromide 12b. Palladium(0)-catalyzed condensation of 12b with vinylstannane 13 provided seco-cembrane 14. Following the elaboration of 14 into bromo aldehyde 16, macrocyclization was effected with chromous chloride. The single homoallylic alcohol produced by this means underwent oxidation to give acerosolide, as deduced by proper spectral comparison with the natural product.