An IMDAF Cycloaddition Approach toward the Synthesis of the Lycopodium Alkaloid (±)-Fawcettidine
作者:Jutatip Boonsompat、Albert Padwa
DOI:10.1021/jo200125c
日期:2011.4.15
Using an intramolecular [4 + 2] cycloaddition/rearrangement cascade of 3-(1,4-dioxaspiro[4.4]non-7-en-7-yl)-N-furan-2-ylpropionamide (23) as the key step, the BCD core of the lycopodiumalkaloid fawcettidine was constructed. Heating the initially formed Diels−Alder cycloadduct at 180 °C results in a nitrogen-assisted ring opening followed by a deprotonation/reprotonation of the ensuing zwitterion to