From 1,2-Azidoalcohols

Aziridines were amongst the first heterocycles to be prepared by synthesis, and they occupy a special place in organic synthesis. This chapter has, we hope, indicated the rich chemistry associated with this area of synthetic endeavor in both the distant and the recent past it is clear that the recent exciting developments in asymmetric aziridine synthesis indicate a most promising future for the practitioners in the field and the greater synthetic community at large. 

Murphree, in Progress in Heterocyclic Chemistry, G. W. Gribble, T. L Gilchrist, Eds. Oxford Pergamon Elsevier Science, 2000 Vol. 12, Chapter 4.1, p. 57. 

31 a) G. Cardillo, S. Casolari, L. Gentiluca, C. Tomasini, Angew. Chem. Int. Ed. Engl. 

Garcia Ruano, I. Fernandez, C. Ham-douchi, Tetrahedron Lett. 1995, 36, 295 J. L Garcia Ruano, I. Fernandez, M. del Prado Catalina, A. A. Cruz, Tetrahedron Asymmetry 1996, 7, 4307. 

Alajarin, R.-A. Orenes, A. Vidal, A. Pastor, Synthesis 2003, 49 for a novel synthesis of non-chiral azirines. 

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The spirocyclic phosphazenes (138) resulting from the reaction with 2-azidoalcohols dimerize <82TL853>. In the adducts of phenols with a heterodiene function in the 2-position <77ZN(B)84l> the phosphorus atom also becomes the center of a tricyclic system (139) (Scheme 45). 

P-Aminoalcohols may be generated from (3-azidoalcohols, which are commonly made from the opening of epoxides with azide ion as shown in Scheme 13 (91TL2533). After conversion of the alcohol... 

Epoxides which are fused to alicyclic systems undergo ring opening with azide ion in the usual tram diaxial manner This is demonstrated by the formation of the /ran5-2-azidoalcohols (66) and (67) from cyclohexene oxide and cyclopentene oxide respectively . 

Sodium azide sulfuric acid 2-Azidoalcohols from oxido compds. 

Sodium azide/sulfuric acid 2-Azidoalcohols from oxido compounds s. 15, 370... 

Monosubstituted epoxides are normally opened by sodium azide at the unsubstituted carbon atom but in the presence of a Lewis acid this preference can be overridden. Thus styrene oxide 64 is opened predominantly at the higher substituted position by sodium azide in the presence of lithium tetrafluoroborate. Diethylaluminium azide has been used for the opening of trisubstituted epoxides and the predominant products are those derived from attack on the tertiary carbon atom. For epoxyalcohols the reagent Ti(OtPr)2(N3)2 has been used to achieve regioselective ring opening. An example of its use is the conversion of epoxyalcohol 65 into azidoalcohols 66 and 67 (Scheme 6.28). ° ... 

Enantiopure aziridines can also be obtained from chiral 1,2-diols. These are converted into cyclic sulfates 68, " or cyclic sulfites 69. These compounds are also cleaved by reaction with lithium azide or sodium azide to azidoalcohols which can then be converted into aziridines as above. The sulfates 68 can be prepared in one pot and in high yield from the diols by reaction with thionyl chloride followed by oxidation with sodium periodate and ruthenium trichloride. Sulfites 69 are available from diols simply by reaction with thionyl chloride. An example of the use of a cyclic sulfate is the preparation of the aziridine 71 in good yield and with high ee from the chiral sulfate 70 (Scheme... 

The radical fragmentation of )5-hydroxy azides has been investigated by Suarez. For example, treatment of an azidoalcohol derived from Umonene with diacetoxyiodobenzene... 

The irreversibility of the latter reaction allowed the formation of the corresponding P-azidoalcohols and P-hydroxynitriles in good to excellent yields and with perfect enantiopurity. As some ADHs, for example, ADH-A from R. ruber used in this study, suffer from inactivation from cyanide, addition of the nucleophile must be carried out after complete reduction of the a-chloro ketone substrate. 

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