The Efficient Synthesis of Morphinandienone Alkaloids by Using a Combination of Hypervalent Iodine(III) Reagent and Heteropoly Acid

• Published in: Chemistry : a European journal 2004-10, Vol.10 (20), p.4977-4982
• Main Authors: Hamamoto, Hiromi, Shiozaki, Yukiko, Nambu, Hisanori, Hata, Kayoko, Tohma, Hirofumi, Kita, Yasuyuki
• Format: Article
• Language: English
• Subjects: Acids - chemistry; alkaloids; Alkaloids - chemistry; CC coupling; heteropoly acids; hypervalent iodine reagents; Iodine - chemistry; Isoquinolines - chemistry; Molecular Structure; Morphinans - chemistry; Oxidation-Reduction; spiro compounds
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200400358

The non‐phenolic coupling reaction of benzyltetrahydroisoquinolines (laudanosine derivatives) by using a hypervalent iodine(III) reagent is described. In general, chemical oxidation of laudanosine gives glaucine. In contrast to general chemical oxidizing reagent systems, the novel use of reagent combination of phenyliodine bis(trifluoroacetate) (PIFA), and heteropoly acid (HPA) afforded morphinandienone alkaloids in excellent yields. In order to achieve the coupling reaction with simple reaction procedure, the use of HPA supported on silica gel instead of HPA was demonstrated and sufficient yield was exerted again. The present reagent system, PIFA/HPA, was also applied to the oxidation of other non‐phenolic benzyltetrahydroisoquinolines and the high yield conversion to morphinandienones was accomplished. The novel use of the remarkable combination of phenyliodine bis(trifluoroacetate) (PIFA) and heteropoly acid (HPA) for the non‐phenolic coupling reaction of benzyltetrahydroisoquinoline derivatives afforded morphinandienone alkaloids in excellent yields for the first time by using chemical oxidation (see scheme).