Tandem Pummerer−Diels−Alder Reaction Sequence. A Novel Cascade Process for the Preparation of 1-Arylnaphthalene Lignans
作者:Albert Padwa、John E. Cochran、C. Oliver Kappe
DOI:10.1021/jo960295s
日期:1996.1.1
which undergoes a subsequent Diels-Alder cycloaddition with added dienophiles. Acid-catalyzed ring-opening of the cycloadduct followed by aromatization gave an arylnaphthalene derivative. With acetylenic dienophiles, the tandem cyclization-cycloaddition sequence provided tetralones which result from a pinacol-type rearrangement of the primary cycloadducts. The versatility of the approach is highlighted
由邻苯甲酰基取代的亚砜的Pummerer反应产生的α-硫代碳原子化被相邻的酮基团截获,以生成α-硫代异苯并呋喃作为过渡中间体,随后进行狄尔斯-阿尔德环加成反应并加入亲二烯体。酸催化环加合物的开环,然后进行芳构化,得到芳基萘衍生物。对于炔属二烯亲和物,串联环化-环加成序列提供了四氢萘酮,其是主要环加合物的频哪醇型重排。该方法的多功能性是通过合成taiwanin C和E以及Justicidin E来突出显示的。苯并[1,3]二恶酚-5-基-[6-[(乙基亚硫酰基)甲基]的Pummerer反应产生的α-硫代碳酸盐化反应苯并[1,3]二氧杂-5-基)甲酮被相邻的酮基团拦截,生成α-硫代异苯并呋喃,作为过渡中间体,随后与马来酸二甲酯进行狄尔斯-阿尔德环加成反应。最初形成的Diels-Alder环加合物易于转化为5-苯并[1,3]二恶唑-5-基-8-(乙硫基)萘并[2,3-d] [1,3]二恶唑-6,