A Bioinspired Synthesis of (±)‐Rubrobramide, (±)‐Flavipucine, and (±)‐Isoflavipucine. (4th July 2016)

• Record Type: Journal Article
• Authors: Mizutani, Shoma; Komori, Kenta; Taniguchi, Tohru; Monde, Kenji; Kuramochi, Kouji; Tsubaki, Kazunori
• Is Part Of: Angewandte Chemie. Volume 128:Number 33(2016)
• Page Start: 9705
• Page End: 9708
• Publication Date: 2016-07-04
• Subjects: Biomimetische Synthesen -- Konfigurationsbestimmung -- Lactame -- Schwingungsspektroskopie -- Totalsynthese; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201602910
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A biomimetic synthesis of naturally occurring lactams rubrobramide, flavipucine, and isoflavipucine is described. The key step is a regioselective Darzens reaction between isobutyl glyoxal and an α‐bromo‐β‐ketoamide. The construction of the core tricyclic ring system of rubrobramide was achieved by a cascade reaction in a single step from an α, β‐epoxy‐γ‐lactam. Furthermore, the absolute configuration of naturally occurring (+)‐rubrobramide was determined by vibrational circular dichroism. (±)‐Flavipucine and (±)‐isoflavipucine were synthesized from an epoxyimide, which was prepared by reaction of isobutyl glyoxal with a protected α‐bromo‐β‐ketoamide. Deprotection of the epoxyimide and formation of the pyridone ring gave (±)‐flavipucine, which was converted into (±)‐isoflavipucine by thermal isomerization.