Camphorylsulfonyl oxaziridine

Miyata, O. Shinada, T. Kawakami, N. Taji, K, Ninomiya, I. Naito, T Date, T. Okamura, K. Chem. Pharm. Bull. 1992, 40, 2579, 

(a) Williams, R. M. Synthesis of Optically Active ot-Amino Acids, Pergamon Oxford, 1989, (b) Oppolzer, W. Arch. Pharm. (Weinheim, Cer.) 1990, 190. (c) Oppolzer, W. Moretti, R, Thomi, S. Tetrahedron Lett. 1989, 30, 6009. (d) Josien, H. Martin, A. Chassaing, G. Tetrahedron Lett. 1991, 32, 6547. (e) Oppolzer, W Lienard, P. Helv. Chim. Acta 1992, 75, 2572. (f) Oppolzer, W. Tamura, O. Tetrahedron Lett. 1990, 31, 991. (g) Oppolzer, W Tamura, O. Deerberg, J. Helv. Chim. Acta 1992,75,1965. (h) Oppolzer, W. Cintas-Moreno, R Tamura, O. Helv. Chim. Acta 1993, 76,187. (i) Oppolzer, W. Merifield, E. Helv. Chim. Acta 1993, 76, 957. (j) Oppolzer, W Bienayme, H. Genevois-Borella, A. J. Am. Chem. Soc. 1991,113,9660. 

Solubility sol THF, CH2CI2, CHCI3 slightly sol isopropanol, ethanol insol hexane, pentane, water. 

Form Supplied in commercially available as a white solid. 

Analysis of Reagent Purity by mp and specific rotation determination. 

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Arylsulfonyloxaziridines, 23 (Camphorylsulfonyl)oxaziridines, 64 Oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide),... 

Oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide), 21 Perbenzoic acid, 238 a to a carbonyl group 2-Arylsulfonyloxaziridines, 23 (Camphorylsulfonyl)oxaziridines, 64 m-Chloroperbenzoic acid, 76, 334 Oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide), 227... 

Acetoxy-l-acetylproline, 251 L-a-Amino-y-butyrolactone, 207 /-Butyl hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 51 (Camphorylsulfonyl)oxaziridines, 64 Cumene hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 52 Diisobutylaluminum hydride-Tin(II) chloride-(S)-1 -[ 1 -Methyl-2-pyrroii-dinyl]methylpiperidine, 116 (S)-Phenylglycine, 225 L-Valine, 226 Crown ethers Benzo-14-crown-4, 143 12-Crown-4, 167 12-Crown-6, 218... 

C. (+)-(2R,8aS)-10-(Camphorylsulfonyl)oxaziridine. A 5-L, three-necked, round-bottomed Morton flask is equipped with an efficient mechanical stirrer, a 125-mm Teflon stirring blade, a Safe Lab stirring bearing (Note 6), and a 500-mL addition... 

Oxidation is generally complete after addition of the oxone solution. The oxidation is monitored by TLC as follows remove approximately 0.5 mL of the toluene solution from the nonstirring solution, spot a 250-micron TLC silica gel plate, elute with methylene chloride and develop with 10% molybdophosphoric acid in ethanol and heating (camphorsulfonyl)imine R = 0.28 and (camphorylsulfonyl)oxaziridine R = 0.62. If (camphorsulfonyl)imine is detected, stirring is continued at room temperature until the reaction is complete (See Note 8). 

Camphorylsulfonyl)oxaziridine described here is prepared in four steps from inexpensive (1S)-(+)- or (1R)-(+)-10-camphorsulfonic acid in 77% overall yield.7... 

ASYMMETRIC OXIDATION OF LITHIUM ENOLATES OF ESTERS AND AMIDES USING (+)-(2R.8aS)-10-(CAMPHORYLSULFONYL)OXAZIRIDINE... 

Chiral Davis oxaziridines allow the oxidation of phosphonates to a-hydroxy-phosphonates in good ee with apparently wide generality and with a sense of induction that is well controlled by the chirality of the reagent used.109 mCPBA oxidation of a bi-cyclic e do-camphorylsulfonylimine surprisingly resulted in an exo-camphorylsulfonyl-oxaziridine, whereas all other camphorylsulfonylimines resulted only in endo-oxaziiidines.110 Asymmetric oxidation of sulfides to sulfoxides and the a-hydroxylation of enolates were predicted by models in which steric interactions are minimized. 

Both isomeric forms of (+)- and (—)-(camphorylsulfonyl)oxaziridines are available by oxidation of the corresponding sulfonimines with buffered potassium peroxymonosulfate (oxone). Since oxidation can only take place from the endo-fa.ce of the C=N double bond due to steric blocking of the exo-face, a single oxaziridine isomer is obtained. The enantiomerically pure sulfonimines can be prepared in three steps in better than 80% yield from inexpensive (+)- and (—)-camphor-10-sulfonic acids. Alternatively they are commercially available200. 

ASYMMETRIC HYDROXYLATION OF TETRALONE AND PROPIOPHENONE ENOLATES USING (CAMPHORYLSULFONYL)OXAZIRIDINES 1 AND 2... 

Deprotonation of allyl ether 233 with t-BuLi in the presence of tetramethylethylenediamine (TMEDA) followed by reaction with (camphorsulfonyl)oxaziridine 202 produced alcohol 234. The product was isolated in 29% yield as the sole geometrical isomer <2005TL3465>. An advantage of using the (camphorylsulfonyl)oxaziridines for these hydroxyla-tions is that the T-sulfonylimine by-product is resistant to addition of the organometallic reagent <1987TL5115>. 

Asymmetric Oxidation of Sulfides. Prochiral sulfides are oxidized by (camphorylsulfonyl)oxaziridine (1) to optically active sulfoxides. Over-oxidation to sulfones is not observed (eq 1 ). However, the best chiral A-sulfonyloxaziridines for the asymmetric oxidation of sulfides to sulfoxides are the (+)- and (Phenylsulfonyl )(3,3-dichlorocamphoryl )oxazi ridinesfi... 

Oxidation of Enamines. Enamines are rapidly oxidized by (+)-(camphorylsulfonyl)oxaziridine (1). Disubstituted enamines give rise to racemic ot-amino ketones, while trisubstituted enamines afford, after hydrolysis, ot-hydroxy ketones (eq 2). A mechanism involving initial oxidation of the enamine to an a-amino epoxide is suggested to account for these products. 

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