Oxazolidinones rearrangement

Compound 219 underwent an easy and novel oxazolidinone rearrangement upon treatment with NaH <03JOC6268>. 

Oxazolidin-5-one, bis(trifluoromethyl)-reactions, 6, 213 Oxazolidinones polymers, 1, 281-282 reactions, 6, 213 Oxazolidinones, imino-rearrangement, 5, 775 Oxazolidinones, vinyl-polymers, 1, 281 Oxazolidin-2-ones circular dichroism, 6, 185 H NMR, 6, 181 IR spectroscopy, 6, 183 PE spectroscopy, 6, 183 reactions, 6, 213... 

Another method for producing a chiral 3-carbon fragment, this time directly as a protected 5-hydroxymethyl-3-oxazolidin-2-one, is illustrated in scheme 9 (77). In this case, the amide 20 is converted to the 4-trityl ether 24. This undergoes very facile Hofmann rearrangement to give the 5-trityloxymethyl-3-oxazolidin-2-one 26 via the intermediate isocyanate 25. The oxazolidinone 26 is a protected version of 3-amino-1,2-dihydroxypropane. 

Roydhouse, M.D. and Walton, J.C. (2007) Formation of a tetracyclic isoquinoline derivative by rearrangement of a [(bromophenyl)butyryl]oxazolidinone. European Journal of Organic Chemistry, 1059-1063. 

The carbene-insertion pathway has recently been applied in total asymmetric syntheses of the anti-leukemic alkaloid, (—)-agelastatin A, and the dibromo analog, (-)-agelastatin B (02JA9060, 02JOC7096). Treatment of the (oxazolidinonyl)propynyliodonium triflate 250 with sodium />-toluenesulfinate leads to a mixture of the bicyclic oxazolidinone 251 and the carbenic rearrangement product 252 (Scheme 70) compound 251 is a key intermediate in the agelastatin synthesis. 

A synthesis of 2-oxazolidinones has been reported by a base-mediated reaction between epichlorohydrin and primary amines. This reaction proceeded via an intermediate hydroxy-l,3-oxazinan-2-one 300, which rearranged to the more stable 2-oxazolidinone product under the reaction conditions (Scheme 84) <2005JOC5737>. 

The enantioselective total synthesis of the cytokine modulator (-)-cytoxazone using a syn-stereoselective aldol addition and a Curtius rearrangement as key steps was described by J.A. Marco et al. The key intermediate acid was treated with DPPA and triethylamine in toluene at reflux. This step furnished the oxazolidinone directly and in good yield through an in situ capture of the isocyanate group by the free secondary alcohol functionality. Removal of the protecting group led to the formation of the natural product. 

Acetylenic cobalt complexes greatly facilitate the heterolytic cleavage of adjacent alcohols or ethers. On treatment with Lewis acids, these complexes afford cobalt stabilized carbenium ions, which can be captured by nucleophiles such as enolates. Jacobi and Zheng have employed chiral boron enolates of Evans s oxa-zolidinone 6.91 (R = i-Pr). After removal of the chiral auxiliary, they obtained anti adds 11.43 with a high selectivity [1677] (Figure 11.9). The reaction can be extended to the boron enolates of related oxazolidinones and to a-branched propargyl derivatives. This reaction has been applied to the synthesis of P-aminoacids after Curtius rearrangement and oxidation of the triple bond [1677]. 

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