Berthold D, van Otterlo WAL. Unprecedented Direct Asymmetric Total Syntheses of 5,8'-Naphthylisoquinoline Alkaloids from their Fully Substituted Precursors Employing a Novel Nickel/N,N-ligand-Catalyzed Atroposelective Cross-Coupling Reaction.
Chemistry 2023;
29:e202302070. [PMID:
37515575 DOI:
10.1002/chem.202302070]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 07/31/2023]
Abstract
A general and concise synthetic pathway for the preparation of four different 5,8'-coupled naphthylisoquinoline alkaloids, employing a specially developed nickel/N,N-ligand-catalyzed atroposelective Negishi coupling is reported. In the first reported direct atroposelective coupling of the fully substituted precursors, the naturally occurring cross-coupled products were generally obtained directly in reasonable yields and high enantiomeric purities. For the synthesis of the cross-coupling precursors, we employed a modification of Bringmann's known approach to the dihydroisoquinoline compounds and a newly developed route for the naphthalene building blocks. For the latter 1,8-dioxynaphthalene precursors, our strategy utilized Hartwig's borylation/methylation approach and included the efficient installation of orthogonal protecting groups.
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