Usnic isousnic acid rearrangement

A synthesis of usnic acid derivatives, incorporating a Diels-Alder reaction similar to that of the synthesis of di-O-methylstrepsilin (Scheme 58), was reported by Elix and Tronson 133). Extensive studies on the chemistry of usnic acid and derivatives have been conducted by Kutney etal. 217—225) and Takahashi etal. 315—321, 324, 326). Included in the work of Kutney etal. was a base-catalysed usnic acid-isousnic acid rearrangement 224, 225), which constituted the first synthesis of isousnic acid (476) (Scheme 64). A mechanism for this rearrangement was proposed (221). 

Scheme 64. Base catalysed usnic acid-isousnic acid rearrangement...

StudiesintheUsnicAcidSeries. V. The Base Catalysed Usnic Acid-Isousnic Acid Rearrangement. Part III. (— )-Usnic Acid Isomethoxide Monoacetate. Can. J. Chem. 55, 1079 (1977). 

Kutney JP, Sanchez IH, Yee T (1977) Studies in the Usnic Acid Series. IV. The Base Catalyzed Usnic Acid - Isousnic Acid Rearrangement. Part II. An Improved Synthesis of (+)-Isousnic Acid. Can J Chem 55 1073... 

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See also in sourсe #XX -- [ ]

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