經由[3+3]硫尿素有機催化下合成非鏡像選擇性之螺環茚吡喃併吡唑化合物

Abstract

本實驗室藉由兩個有機小分子進行有機連鎖反應，發展出高非鏡像選擇之螺環茚吡喃併吡唑化合物。使用吡唑酮與四取代烯烴，利用 20 mol %的硫尿素衍生之有機催化劑及20 mol %的 4-二甲氨基吡啶，經由[3+3]合環反應，Michael/Acetalization 反應，生成多官能基的螺環茚吡喃併吡唑化合物，其具有不錯的產率（高達 94 %）及優異的非鏡像選擇性（高達> 20:1 dr）。此外，也經由單晶繞射 X-ray 確認其產物相對立體組態。而螺環茚吡喃并吡唑化合物尚未有相關文獻報導，期許此方法能應用於天然物之合成上。An organocascade reaction between pyrazolone and arylallylilidene-indene-1,3-diones derivated tertiary substituted alkene has been developed to a [3+3]-cycloaddtion leading functionalized dihydrospiro[indene-2,4'-pyrano[2,3-c]pyrazole]-1,3-dione frameworks. The reaction mediated by thiourea derived organocatalyst proceeds via Michael/Acetalization reaction in high yields and with excellent diasteroslectivity (up to >20:1dr). The relatived configuration of the cyclized product was determined by the single crystal X-ray analysis