A New Highly Efficient Three-Component Domino Heck–Diels–Alder Reaction with Bicyclopropylidene: Rapid Access to Spiro[2.5]oct-4-ene Derivatives Part 77 in the series “Cyclopropyl Building Blocks in Organic Synthesis”. For Part 76 see: S. Wiedemann, I. Marek, A. de Meijere, Synlett 2002, submitted. Part 75: M. W. Nötzel, K. Rauch, T. Labahn, A. de Meijere, Org. Lett. 2002, 4, 839–841.
作者:Hanno Nüske、Stefan Bräse、Sergei I. Kozhushkov、Mathias Noltemeyer、Mazen Es-Sayed、Armin de Meijere
DOI:10.1002/1521-3765(20020517)8:10<2350::aid-chem2350>3.0.co;2-e
日期:2002.5.17
three-component reaction with a variety of dienophiles to furnish the domino Heck-Diels-Alder products 18 regioselectively in most cases in good to very high yields (49-100 %). The reaction of 1 with iodobenzene (2-Ph) and 17 a gave 18 a-Ph in virtually quantitative yield-also on a gram scale-using only 1 mol % of catalyst, and even bromobenzene (22) gave 18 a-Ph in 59 % yield. Bicyclopropylidene (1), in the
发现双环亚丙基(1)在用芳基或烯基钯进行碳钯反应的速率上甚至超过丙烯酸甲酯(17a),从而导致取代的亚芳基亚环丙烷5、7和10大部分以高收率(37-78%)形成。这些二烯和交叉共轭三烯以Diels-Alder模式与亲二烯体反应,分别以良好的收率得到螺[2.5]辛烯18 a-Ph,18 b-Ph和18 a-Vin(89%,69%和65% )。可以通过与多种亲二烯体的单锅三组分反应来实现整体转化,从而在大多数情况下以良好或非常高的收率(49-100%)选择性地提供多米诺Heck-Diels-Alder产品18。1与碘代苯(2-Ph)和17a的反应可得到几乎定量的收率18a-Ph,也以克为单位,仅使用1 mol%的催化剂,甚至溴苯(22)也能以18%的收率获得18 a-Ph。在乙酸钯/三苯膦存在下的双环亚丙基(1)经过重排反应生成烯丙基亚环丙烷(5-H),后者在没有其他反应伙伴的情况下又二聚(7