Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig (Germany); Permanent Address: Faculty of Chemistry, Jagiellonian University Krakow, Ingardena 3, 30060 Krakow (Poland).
Angew Chem Int Ed Engl. 2014 Jul 21;53(30):7923-7. doi: 10.1002/anie.201403573. Epub 2014 Jun 18.
We describe herein a catalytic, enantioselective process for the synthesis of 4H-chromenes which are important structural elements of many natural products and biologically active compounds. A sequence comprising a conjugate addition of β-diketones to in situ generated ortho-quinone methides followed by a cyclodehydration reaction furnished 4-aryl-4H-chromenes in generally excellent yields and high optical purity. A BINOL-based chiral phosphoric acid was employed as a Brønsted acid catalyst which converted ortho-hydroxy benzhydryl alcohols into hydrogen-bonded ortho-quinone methides and effected the carbon-carbon bond-forming event with high enantioselectivity.
我们在这里描述了一种催化、对映选择性的合成 4H-色烯的方法，4H-色烯是许多天然产物和生物活性化合物的重要结构单元。该序列包括β-二酮的共轭加成到原位生成的邻醌甲醚，然后进行环脱水反应，通常以优异的收率和高光学纯度得到 4-芳基-4H-色烯。手性磷酸 BINOL 被用作布朗斯特酸催化剂，将邻羟基二苯甲醇转化为氢键邻醌甲醚，并以高对映选择性实现碳-碳键形成反应。
