Oppolzer’s camphor sultam

Kim B. H., Curran D. P. Asymmetric Thermal Reactions With Oppolzer s Camphor Sultam Tetrahedron 1992 49 293-318... 

Oligomers Oppolzer s camphor sultam (see also camphor derivatives) Organometallics Organosilicon Organosulfur Organozirconocenes Orthoquinodimethanes Oxabutadienes Oxanorbornadiene(s) Oxazinolactams Oxazinones Oxazoles... 

Asymmetric cyclopropanol formation has been achieved with olefmic acylsulfonamides, which act like olefmic esters. Thus, their reaction with 1 provides a method for synthesizing cyclopropanols in an optically active form. As represented by Eq. 9.41, alkylation of Oppolzer s camphor sultam and reaction of the resulting unsaturated acylsulfonamides with 1 provides optically active bicyclic cyclopropanols having exclusively the structure shown in the equation [76],... 

A potential method for the preparation of novel amino acids via the highly selective addition of radicals to the glyoxylic oxime derivative of Oppolzer s camphor sultam (88) has been reported.181 Both Lewis acid and non-Lewis acid-mediated reaction conditions for the addition of alkyl radicals generated from alkyl iodides and Et3B/Bu3SnH were examined. A new chiral auxiliary based upon (R,R)-2,5-diphenylpyiTolidine has been used in the addition of phenylthiyl radicals to unsaturated methacrylamides. The selectivity was found to be better than that reported for the structurally related 2,5-dimethylpyrrolidine derivative.182... 

Oppolzer s camphor sultam, a well known chiral auxiliary, has been applied to the asymmetric synthesis of chial fluorine-containing amino acids <07OL2513>. Photoinduced addition of perfluoroalkyl iodides 189 to /V-acyloylcamphorsultam 188 in the presence of an aqueous solution of sodium sulfite provides alkyl iodides 190 with moderate to good stereoselectivities. Azide displacement with the major diastereomer of 190 proceeds with inversion of configuration. Subsequent removal of the sultam auxiliary and hydrogenation of the azide afford the chiral fluorine-containing amino acid 192. 

The sulfur ylides 254 used in the stereoselective [2,3]-sigmatropic rearrangement are generated by copper(I)-catalyzed Doyle-Kirmse reaction of aryl sulfides 253 and diazo compounds bearing Oppolzer s camphor sultam auxiliary 252 in the presence of chiral diamine ligand S, S)-259 <05JA15016>. These intermediate ylides undergo spontaneous... 

Chiral auxiliaries are capable of controlling the absolute steric course of radical reactions. 8-Phenylmenthyl ester or an amide derived from Oppolzer s camphor sultam can be utilized for enantioselective ring closure to cyclopentane, the chiral auxiliary directing the addition to the alkene. The reductive radical cyclization of 8-phenylmenthyl 2-phenylthio-6-heplenoale at 80 °C gives four isomeric cyclopentane derivatives in an overall yield of 90 % 3. The reaction proceeds with modest cis irons ratio, but a considerably higher RiS selectivity of 80 20. 

Other uses of oxazinone enolates have been described by Williams, including the boron enolate 60, in the synthesis of diaminopimelic acid (62), the penultimate precursor of the essential amino acid i.-lysine (Scheme 10.8) [59], Acylated derivatives of Oppolzer s camphor sultam 63 can readily be alkylated in a highly diastereoselective fashion (Scheme 10.9) [60]. Thus, the imide derived from the condensation of 63 and 64 undergoes enolization and subsequent alkylation to furnish protected amino acid derivatives with high selectivity (cf 65, dr > 99 1) [61],... 

Curran identified Oppolzer s camphor sultam (cf. 81) [77] as a superb chiral auxiliary for the asymmetric [l,3]-dipolar cycloadditions of nitrile oxides (Scheme 18.17) [78-80]. The resulting cycloadducts were generally obtained with high diastereofacial selectivity (dr 90 10). It was proposed that the observed facial differentiation was the result of attack by the nitrile oxide from the top face of conformer 84. This was suggested to be favored on the basis of electronic and steric effects, a proposition that finds support in an X-ray structural analysis of 81 [78, 80]. Cycloaddition of 81 with the nitrile oxide generated in situ from 80 led to isoxazoline 82 in 89 % yield (dr= 92 8). This product constituted a key intermediate in Curran s total synthesis of 83, a bicyclic ketal isolated from ambrosia beetles [80]. 

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