Comforth oxazole rearrangements

Configuration, inversion of -Cope rearrangement Comforth oxazole rearrangements deamination-rearrangement homoallyl -migration... 

Copyrolysis 31,791 Corey oxidation 28,201 Comforth oxazole rearrangement 31, 318 Corrins... 

Williams and McClymont have observed that acylation reactions of the dianion of 2-(5-oxazolyl)-l,3-dithiane (15) lead to formation of 4,5-disubstituted oxazole products through a Comforth rearrangement pathway under base-induced, low-temperature conditions. For example, deprotonation of 15 with LiHMDS (3.0 equivalents) at -78°C, followed by addition of benzoyl chloride or p-chlorobenzoyl chloride and warming to 0°C, provided 16 in 74% and 47% yield, respectively. 

A microwave assisted Comforth rearrangement of oxazole-4-carboxamides 106 efficiently afforded 5-aminooxazole-4-carboxylates 107. This procedure was applied to the formal synthesis of a natural antibiotic derived from pseudomonic acid <06TL4698>. 

Williams, D. R. McClymont, E. L. Carbanion methodology for alkylations and acylations in the synthesis of substituted oxazoles. The formation of Comforth rearrangement products. Tetrahedron Lett. 1993, 34, 7705—7708. 

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