Preparation and conformational studies of chiral camphor-derived oxaziridines

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

“…The carbonyl group in 3 can be selectively protected as an acetal by reaction with orthoformates at room temperature in the presence of an acid. Thus, 3,3-dimethoxycamphersulfonylimine 16 and 3,3-diethoxycamphersulfonylimine 16’ were prepared [18,39]. The subsequent reaction of these acetals with one equivalent of lithium phenylacetylide or 1-heptynyllithium under conditions described above for the synthesis of 12 and 13 introduced the alkyne into the 2-position of the camphor skeleton, to provide the sultams 17 .…”

Multinuclear magnetic resonance study of oxaziridines

“…A conformational study of 18 and similar oxaziridines by NOE measurements has been performed. 26 We shall report on the synthesis and properties of the fenchone-derived oxaziridine 21 elsewhere. mined in CDCIJ for al1 nuclei; this is a much better solvent for this purpose, despite the lower solubility of many sulphonyl oxaziridines.…”

“…The endo-and exo-3-bromo-camphorsulphonyloxaziridines 13 and 14 can be separated from the mixture described in Ref. 26 by chromatography on silica gel. { Chernical Abstracts name: (4aS$aR)-8,8-dibrom0-9,9-…”

Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

“…1 ) shows an especially versatile chemistry. The C=O double bond can be converted to ketals, thioketals or even dihalogenomethylenes [ 1 ] or react to form hydrazones [ 2 ]. On the other hand the C=N double bond can be converted into an oxaziridine group forming chiral oxaziridines which act as enantioselective oxidation reagents [ 1 , 3 – 5 ].…”

“…The C=O double bond can be converted to ketals, thioketals or even dihalogenomethylenes [ 1 ] or react to form hydrazones [ 2 ]. On the other hand the C=N double bond can be converted into an oxaziridine group forming chiral oxaziridines which act as enantioselective oxidation reagents [ 1 , 3 – 5 ]. Other types of reactions include the alkylation of the imine nitrogen atom followed by ring annulation [ 6 ], cleavage of the sulfonimine [ 7 – 8 ] or camphor [ 9 ] rings, reduction of the CO or CN double bonds [ 10 ], addition of acetylide anions to form dialkynes that can undergo complex skeletal rearrangements and unusual redox reactions [ 11 – 14 ].…”