Two valuable reagents for the cis-specific vicinal cyanohydroxylation and carboxyhydroxylation of olefins are described. The cyanohydroxylation process is based on the decarboxylative ring opening of 3-carboxyisoxazolines prepared by the [3 + 2] cycloaddition reaction of carbethoxyformonitrile oxide with various alkenes. Fragmentation of the isoxazolines prepared from cis- and trems-2-butene has been found to occur without any crossover in stereochemistry. The carboxyhydroxylation process begins with the dipolar cycloaddition reaction of the nitrile oxide derived from the tetrahydropyranyl ether derivative of 2-nitroethanol. Deprotection, hydrogenation, and oxidative cleavage of the derived dihydroxy ketone yield the stereochemically pure β-hydroxy carboxylic acid.
ASJC Scopus subject areas
- Organic Chemistry