Camphorsulfonyl

Calcium carbonate as support for palladium catalyst, 46, 90 Calcium hydride, 46, 58 D,L-Camphor, sulfonation to d,l-10-camphorsulfonic acid, 46,12 10-Camphorchlorosulfoxide, 46, 56 d,l-10-Camphorsulfonic acid, 46,12 conversion to acid chloride, 45,14 10-Camphorsulfonyl chloride, 45, 56 d,l-10-Camphorsulfonyl chloride,... 

Oxidation, of d,l 10-camphorsulfonyl chloride to d,l ketopime acid with potassium permanganate, 46, 55... 

David-Thieffiry oxidation 542 Davis s (camphorsulfonyl)-oxa-ziridine 725,728 Davis s oxaziridine 459 DCBI 697 f. 

The Aggarwal group has used chiral sulfide 7, derived from camphorsulfonyl chloride, in asymmetric epoxidation [4]. Firstly, they prefonned the salt 8 from either the bromide or the alcohol, and then formed the ylide in the presence of a range of carbonyl compounds. This process proved effective for the synthesis of aryl-aryl, aryl-heteroaryl, aryl-alkyl, and aryl-vinyl epoxides (Table 1.2, Entries 1-5). 

The reaction of chiral sulfones 161, derived from (lS)-( + )-10-camphorsulfonyl chloride, with cyclopentadiene gives predominantly the endo adduct in a diastereomeric ratio of 91 9 from which one diastereomer 162 can be isolated in pure form by recrystallization (equation 115)109. 

In 2000, these workers described disulfonamide ligands derived from camphor, which could be easily prepared from chiral camphorsulfonyl chloride, and further successfully used in the enantioselective addition of ZnEt2 to... 

It was independently found by two groups that the exo-diol derived from bis(camphorsulfonyl)-substituted tra .s-cyclohexane-1,2-diamine ligand (HOCSAC) was an excellent promoter for the enantioselective addition of dialkyIzinc reagents to any type of ketones, even dialkyl ketones, in the presence of Ti(Oi-Pr)4. As shown in Scheme 4.11, excellent enantioselectivities of up to 99% ee were obtained in these conditions in combination with high yields and with a low catalyst loading of 2-10 mol%. 

After finding the right combination for the diamine linkers, Yus et al. tried to determine whether it was compulsory to use two isoborneol-10-sulfonamide moieties. In this context, these authors have prepared the ligand depicted in Scheme 4.24 by reaction of the best amine linker, trani-cyclohexane-1,2-diamine, with camphorsulfonyl chloride and then with methanesulfonyl chloride, followed by reduction with AlH(i-Bu)2 and then hydrolysis.When this new ligand was involved in the enantioselective addition of ZnEt2 to acetophenone, the expected tertiary alcohol was obtained in excellent yield and enantioselectivity of 96% ee, as shown in Scheme 4.24. According to this result, the authors concluded that the second isoborneol unit seemed not to be necessary to obtain a high enantioselectivity. 

FIOCSAC bis(camphorsulfonyl)-substituted trans-cyclohexane-1,2-diamine... 

Enantioselective synthesis of a-hydroxy phosphonates can also be achieved by asymmetric oxidation with camphorsulfonyl oxaziridines (Scheme 2-60).156 Reasonable yields can usually be obtained. (+)-147a or (+)-147b favors formation of the (S )-product, as would be expected, because these oxidations proceed via a transition state that parallels that previously discussed for the stereoselectivity observed with ketones.157... 

D,L-10-Camphorsulfonyl chloride may be oxidized to ketopinic acid (p. 55). The optically active forms of the sulfonyl chloride are useful for resolving alcohols and amines into optical antipodes. 

The camphorsulfonyl chloride is the crude product obtained as described on p. 14. If it is not carefully dried, it should be oxidized reasonably promptly after its preparation. The oxidation is conveniently carried out in 100-g. portions. Several reactions can easily be carried out in parallel. 

D,L-Ketopinic acid has been prepared by oxidation of bornyl chloride with nitric acid at 20° or with perbenzoic acid in acetic acid from 10,10-dinitrocamphan-2-on or apocamphan-2-ol-l-carboxylic acid with alkaline permanganate and from the oxidation of 10-camphorchlorosulfoxide, obtained from 10-camphorsulfonyl chloride by the action of pyridine, with potassium permanganate. The present procedure represents a simplification of the latter and gives as high an overall yield. ... 

Camphorsulfonyl chloride is rather rapidly hydrolyzed by warm water. The procedure here provides for complete hydrolysis of phosphorus oxychloride and excess phosphorus pentachloride without local heating and loss of product due to hydrolysis. For best results, the whole hydrolysis operation should be carried out quickly and steadily. It is well to have additional quantities of crushed ice on hand because the mixture may become quite hot if all of the ice added initially melts. 

D-lO-Camphorsulfonyl chloride, 48, 107 reaction with diazomethane and triethylamine, 48, 106 d,i,-10-Camphorsulfonyl chloride,... 

Fluorination of the sodium enolate of 2-methyl-1-tetralone by (-)-A-tluoro-2,10-(3,3-dichlorocamphorsultam) gives (5 )-(- -)-2-iluoro-2-methyl-1-tetralone in 70% ee, which corresponds to the opposite asymmetric induction to that achieved using non-racemic (camphorsulfonyl)oxaziridines as closely related hydroxylation reagents. ... 

The use of chiral leaving groups, e.g.. a camphorsulfonyl group, in substitution reactions with C-C bond formation was first reported in 19745. Since the leaving group is involved in the transition state of SN2 reactions, asymmetric induction is observed if a chiral leaving group is used. 

Thus, reaction of tetrahydrofuroic acid (40-1) with triphenylphosphoryl azide leads to isocyanate (40-2). Treatment of this intermediate with benzyl alcohol then affords the corresponding carbamate (40-3). Catalytic hydrogenation removes the benzyloxy group, leading to the free primary amine. That product is then resolved by way of its camphorsulfonyl salt to afford (40-5). Reaction of this intermediate with desamino chloroadenosine (40-6) affords tecadenoson (40-7) [42]. 

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