Aziridine sulfate cyclic

Functionalized aziridines, especially optically active ones, are important intermediates in organic synthesis. The reaction of cyclic sulfates prepared from homochiral diols with amines or azide ion provides an efficient route to homochiral aziridines (equation 56). Formation of aziridines from cyclic sufates occurs with inversion at the stereogenic center. The reaction of the cyclic sulfates with an excess of a primary amine gives /2-... 

TABLE 5. Preparation of N-substituted aziridines from cyclic sulfates... 

Although the Sharpless asymmetric epoxidation is an elegant method to introduce a specific defined chirality in epoxy alcohols and thus, in functionalized aziridines (see Sect. 2.1), it is restricted to the use of allylic alcohols as the starting materials. To overcome this limitation, cyclic sulfites and sulfates derived from enantiopure vfc-diols can be used as synthetic equivalents of epoxides (Scheme 5) [12,13]. 

Alternatively, the remaining sulfate ester of 70 may serve as a leaving group for a second nucleophilic displacement reaction. When this displacement is by an intramolecular nucleophile, a new ring is formed, as was first shown in the synthesis of a cyclopropane with malonate as the nucleophile [68] and of aziridines with amines as the nucleophiles [76]. The concept is further illustrated in the double displacement on (/J,/ )-stilbenediol cyclic sulfate (72) by benzamidine (73) to produce the chiral imidazoline 74 [79]. Conversion of the imidazoline (74) to (.V,.S )-stilbenediaminc 75 demonstrates an alternative route to optically active 1,2-diamines. Acylation of 75 with chloroacetyl chloride forms a bisamide, which, after reduction with diborane, is cyclized to the enantiomerically pure trans-2,3-diphenyl- 1,4-diazabicy-clo[2.2.2]octane (76) [81],... 

Aziridines amino alcohols.1 The 1,2-cyclic sulfates (1) of chiral diols react with RNH2 to form 3-amino sulfates (2), which are convertible into aziridines or amino alcohols. 

B. B. Lohray, Cyclic Sulfites and Cyclic Sulfates Epoxide Like Synthons, Synthesis 1992, 1035-1052. J. B. Sweeney, Aziridines Epoxides Ugly Cousins Chem. Soc. Rev. 2002, 31, 247-258. 

From Cyclic Sulfates and Thionocarbonates. 10.4 From Aziridines and 2-Oxazolidinones. 10.5 From 1,2,3-Selenadiazoles 1,3,4-Selenadiazolines. 10.7 From 4-Selena-3,5-dihydropyrazoles. 10.8 From Selenepines and Tellurepines... 

In the route to amino phosphonic acids, dialkyl l-(alkoxycarbonyl)methylphosphonates, in the presence of NaH in THF or DME, are alkylated with activated aziridines, 3-aIkoxyazetidinium salts, ° ° and cyclic sulfate derived from (5)-l,2-propanediol ° ... 

If the cyclic sulfate is initially opened with a sec-amine, the intramolecular displacement leads to a quaternary aziridine ion 229, which can be opened by a second nucleophile in a sequential triple displacement (95TL9241) leading to substituted amines 230, as shown in Scheme 58. 

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... 

Scheme 6.29 The use of cyclic sulfates and sulfites for the preparation of aziridines - ...

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