Synthesis of the ABCD Trioxadispiroketal Subunit of Azaspiracid-1: An Iodoetherification−Dehydroiodination Strategy for Complex Spiroketals
作者:Xiaohua Li、Jialiang Li、David R. Mootoo
DOI:10.1021/ol701866v
日期:2007.10.1
An unusual spiroketalization strategy in which a hydroxyalkene serves as a precursor to a cyclic enol ether was applied to the synthesis of the ABCD trioxadispiroketal subunit of azaspiracid-1. The trioxadispiroketal product, which represents a double anomeric effect, was obtained as a single trioxadispiroketal diastereomer. A key ploy in the synthesis of the CD segment was the use of a cyclopropane as a synthon for the C-14 methyl group.