Photochemical Synthesis of Cyclopenta[<b><i>c</i></b>]-Anellated Benzopyrans and Benzothiopyrans
作者:Paul Margaretha、Dirk Schwebel、Marko Soltau
DOI:10.1055/s-2001-15053
日期:——
On irradiation in the presence of 2,3-dimethylbut-2-ene the newly synthesized 2-oxo-2H-1-benzopyran- and 2-oxo-2H-1-benzothiopyran-4-carbonitriles are converted selectively to a cyclopenta[c]benzopyran or -thiobenzopyran, respectively. The reaction proceeds via addition of the alkene to the nitrile- and olefinic C-atoms of the triplet excited coumarin derivatives.
在存在2,3-二甲基丁-2-烯的辐照下,新合成的2-氧代-2H-1-苯并吡喃和2-氧代-2H-1-苯并噻吡喃-4-碳腈被选择性转化为环戊烯[c]苯并吡喃或-噻苯并吡喃。该反应通过烯烃与三重态激发的香豆素衍生物的腈碳和烯烃碳原子的加成进行。