A Novel Synthesis of Berbines1-Synthesis of 2,3-Dimethoxy-10,11-Methylenedioxyberbine by Use of Palladium Catalyzed Insertion of Carbon Monoxide
- 1 January 1979
- journal article
- research article
- Published by Taylor & Francis in Synthetic Communications
- Vol. 9 (10) , 895-900
- https://doi.org/10.1080/00397917908064211
Abstract
Palladium catalyzed amidation has recently been reported for the synthesis of benzolactams2. We wish to report a simple and efficient method for the synthesis of berbines by the Palladium catalyzed insertion of carbon monoxide under mild reaction conditions such as an atmospheric pressure of carbon monoxide at 95° by use of a catalytic amount of Pd(OAc)2 and PPh3 in presence of a tertiary amine. The approach has wider applicability in the berbine synthesis3 as examplified by the synthesis of 2,3-dimethoxy-10,11-methylene-dioxyberbine 7. The bromo-1-benzyl tetrahydroisoquinoline derivative 5 4, the key precursor, was prepared from the known reaction sequence involving an Schotten-Baumann condensation5 and B.N. reaction followed by sodium borohydride reduction.Keywords
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