Copper-Catalyzed Cascade Synthesis of 2‑Aryl-3-cyanobenzofuran and Dibenzo[<i>b</i>,<i>f</i>]oxepine-10-carbonitrile Derivatives

The copper-catalyzed reaction of aryl aldehydes with 2-iodobenzylcyanides afforded 2-aryl-3-cyanobenzofurans in isolated yields of up to 74% in a cascade manner, which involves Knoevenagel condensation, aryl hydroxylation, oxa-Michael addition, and aromatization reactions. Conversely, 2-halo benzaldehydes as reacting partners with 2-iodobenzylcyanide regioselectively furnished dibenzo­[b,f]­oxepine-10-carbonitrile derivatives up to 85% isolated yields via tandem Knoevenagel condensation, aryl hydroxylation, and Ullmann coupling reactions.铜催化芳基醛与2-碘苄基氰(2-iodobenzylcyanides)发生级联反应，以最高74%的分离收率得到2-芳基-3-氰基苯并呋喃，该级联过程包含克脑文盖尔缩合(Knoevenagel condensation)、芳基羟基化、氧杂迈克尔加成与芳构化反应。 反之，当2-卤代苯甲醛作为反应底物与2-碘苄基氰反应时，可通过串联克脑文盖尔缩合、芳基羟基化与乌尔曼偶联(Ullmann coupling)反应，区域选择性地生成二苯并[b,f]氧杂卓-10-甲腈衍生物，分离收率最高可达85%。