Synthetic strategies based on aromatic metalation - cross coupling links. regiospecific synthesis of the phenanthrene natural product gymnopusin

✍ Scribed by X. Wang; V. Snieckus

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 126 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)93485-3

✦ Synopsis

An efficient synthesis of gymnopusin (2) using ortho metalation, Suzuki cross coupling, and new anionic Fries rearrangement (3) steps has been achieved.

Gymnopusin, an unusual C-9(-10)-oxygenated phenanthrene isolated from Bulbophyllum gymnopus (Orchidaceae) was originally assigned structure 1,1 but was reassigned structure 2 on the basis of reinterpretation of spectral data2, 3 and synthesis of both 1 and 2. 3 As part of efforts aimed to develop combinational directed ortho metalation -cross coupling strategies, 4 we also synthesized 5 1 by application of our new general route to 9-phenanthrols 6 and established its nonidentity with the natural product. Herein we report a total synthesis of gymnopusin which illustrates the versatility of the aromatic metalation 7 -cross coupling 8 connection (Scheme 1, 4 + 5 ~ 3) and incorporates a new remote anionic Fries rearrangement 9 (3).