Z-ore E-configurated γ-alkylidenebutenolides from a 2- (trimethylsiloxy)furan and iodomethacrolein - Stereoselective synthesis of Z- and E-freelingyne

Article abstract of DOI:10.1016/S0040-4039(98)00240-8

The γ-(α-hydroxylalkyl)butenolides lk-5 and ul-5 were prepared by Mukaiyama aldol additions between iodoaldehyde 10 and the trimethylsiloxy-substituted furan 6 in the presence of BF₃·OEt₂ and ZnBr₂, respectively. Couplings of these butenolides with 3- ethynylfuran followed by anti-eliminations of water mediated by DEAD/PPh₃ led to Z-freelingyne (Z-11 dy = 92:8) anti E-freelingyne (E-11: ds = 98:2).