Lewis Acid-Promoted Hetero Diels−Alder Cycloaddition of α-Acetoxynitroso Dienophiles
作者:Géraldine Calvet、Marion Dussaussois、Nicolas Blanchard、Cyrille Kouklovsky
DOI:10.1021/ol0491336
日期:2004.7.1
[reaction: see text] alpha-Acetoxynitroso compound 3 has been prepared as a new stable, isolable, and reactive dienophile in nitroso Diels-Alder reactions. The yield of the [4 + 2] cycloaddition of alpha-acetoxynitroso dienophile with 1,3-dienes could be enhanced in the presence of 20 mol % Lewis acid. An unexpected retro hetero-Michael reaction from 26 was observed, leading to the cleavage of the
[反应:见正文]在亚硝基Diels-Alder反应中,α-乙酰氧基亚硝基化合物3被制备为新的稳定,可分离和反应性的亲二烯体。在存在20mol%路易斯酸的情况下,可以提高α-乙酰氧基亚硝基二烯亲和体与1,3-二烯的[4 + 2]环加成的产率。观察到来自26的意外的逆杂迈克尔反应,导致环加合物的NO键断裂。该串联亚硝基Diels-Alder /复古异-迈克尔序列已与环状和非环状的1,3-二烯一起使用。