Mesylates MCPBA

Acylated or mesylated aldehyde adducts 301 react with enol silyl ethers 302 to provide products 303, after a phenylsulfanyl migration reaction. Oxidation of compounds 303 with MCPBA followed by heating under mesitylene reflux and acidic hydrolysis afforded 1,3-diketones 304, whereas treatment with potassium fert-butoxide followed by acidic hydrolysis provided 1,4-diketones 305 (Scheme 79)478. 

Sulfoxides are readily available via oxidation of sulfides with peroxycarboxylic acids (e.g., mCPBA, 1.0 eq) or sodium or potassium periodate. The sulfides themselves can be prepared by nucleophilic displacement of tosylate or mesylate esters with sodium alkyl- or phenylsulfides. In the example shown below, the sulfoxide approach worked better than direct E2 elimination of the mesylate precursor. ... 

The synthesis of the preceding vinyl amino sulfone offers a very good example of a stereospecific sulfide-directed epoxidation (Scheme 76).Oxidation of optically active sulfide alcohol (12 readily made from epoxycyclopentadiene and resolved) with MCPBA affords the corresponding sulfoxide, which is in equilibrium with the sulfenate ester. Treatment with pyridine hydrobromide and then phenyl disulfide and bromine gives the bromodiol (13), which is simply cyclized to the epoxide with aqueous sodium hydroxide solution (83% overall yield from the sulfoxide). Treatment of the P-epoxy sulfone with DBU followed by in situ silylation with f-butyldiphenylsilyl chloride affords an 86% yield of vinyl sulfone (14). Mesylation of the alcohol moiety followed by immediate treatment with dimethylamine produces the amino vinyl sulfone via a syn Sn2 substitution. ... 

Wittig methylenation of 3,5-di-0-benzyl-2-deoxy-D-erythrofuranose then reaction with MCPBA-boron trifluoride etherate afford 2,5-anhydro-4,6-di-0-benzyl-3-deoxy-D-ribohexitol. Mesylation of the latter followed by addition of the anion derived from adenine, furnished derivative 11. Cytidine and thymidine could be treated in a similar manner and de-O-benzylated by standard methods. Structures were verified by X-ray analysis. ... 

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