Aminolysis of glycal-derived allyl epoxides and activated aziridines. Effects of the absence of coordination processes on the regio- and stereoselectivity

The addition of primary and secondary aliphatic amines to glycal-derived allyl epoxides is completely 1,2-regio- and anti-stereoselective, whereas mixtures of the corresponding anti-1,2- [3-N-(substituted-amino) glycals] and anti-1,4-addition products (N-glycosyl amines) are obtained with N-(mesyl)-aziridines. In this way, structural moieties, otherwise difficult to synthesize, are obtained by means of a very simple protocol. The regio- and stereoselectivity observed with epoxides is the consequence of an isomerization process, whereas the result obtained with aziridines is explained by the absence of an effective substrate-nucleophile (amine) coordination.     

Azacycloalkanes from epoxides and aziridines

Methods of preparation of azetidines, pyrrolidines, and piperidines from epoxides and aziridines were analyzed. The possibility of epoxides conversion into aziridines was considered. The examples of application of azacycloalkanes in the medical and organic chemistry as biologically active substances and synthons for their preparation were calculated.     

锌和锡参与下末端环氧化物的选择性烯丙基化反应

烯丙基溴和金属辛或锡成功地将末端环氧化合物1一锅法合成高烯丙基醇2和双高烯丙基醇3. 还研究了环氧化合物取代基的影响, 并提出了此烯丙基化的反应途径 .     

Synthesis of quaternary allylammonium salts via ring opening of 1-benzyl-2-(bromomethyl)aziridines

Treatment of 1-benzyl-2-(bromomethyl)aziridine, and some aryl substituted analogues, with an excess of iodomethane resulted in N-allyl-N-benzyl-N,N-dimethylammonium salts, in good yields. These quaternary allylammonium salts are of importance in different fields, from organic synthesis and polymeric chemistry to agricultural use.     

α-Lithiation-rearrangement of N-toluenesulfonyl aziridines with sec-butyllithium and (−)-sparteine: opposite sense of asymmetric induction to epoxides

The α-lithiation rearrangement of three cyclic N-toluenesulfonyl (tosyl) aziridines has been carried out using sec-butyllithium/(−)-sparteine. In each case, it was established that preferential lithiation of the S-aziridine stereocentre occurred. This is the opposite sense of asymmetric induction to that observed with epoxides.     

Stereoselective synthesis of heterosubstituted aziridines and their functionalization

Lithiated (α-chloroalkyl)heterocycles, generated by deprotonation with LDA at −78 °C in THF, add to various enantiopure imines affording ‘one pot’ chiral heterosubstituted aziridines in a diastereoselective manner. Lithiated heterosubstituted aziridines, obtained by deprotonation of the corresponding aziridines with n-BuLi at −78 °C in THF, were trapped by electrophiles (D₂O or CH₃I) with high stereoselectivity.     

Homo-Brook route to benzazocenols and congeners via allylsilane-derived aziridines

We describe a concise entry to benzazocenols intermediates for mitomycinoids via a homo-Brook rearrangement–ring opening sequence of a silylated aziridine. The latter is obtained by intramolecular 1,3-dipolar cycloaddition of an azide with an allylsilane, followed by irradiation of the resulting triazoline.     

Organolithium-induced synthesis of acyclic unsaturated amino alcohols from epoxides of dihydropyrroles and tetrahydropyridines

The alkylative double ring-opening of Bus-protected 2,5-dihydropyrrole epoxides 13 and 29 with organolithiums to give 3-substituted 1-aminobut-3-en-2-ols 13-19 and 30-32 are described. Bus-protected tetrahydropyridine epoxide 38 reacts with organolithiums to give 4-substituted 1-aminobut-4-en-3-ols 39 and tetrahydropyridinol 40.     

New one-pot procedure for the synthesis of diprotected amino alcohols from unprotected vinyl aziridines

An unprecedented one-pot reaction that allows the synthesis of diprotected amino alcohols from unprotected vinyl aziridines is reported. The results demonstrate the possibility to use various acyl chlorides in order to obtain differently functionalised fragments. Mechanistic insights are given.     

Calcium trifluoromethanesulfonate-catalysed aminolysis of epoxides

Aminolysis of epoxides catalysed by calcium trifluoromethanesulfonate under mild reaction conditions is described. The novel method is very efficient in the synthesis of wide variety of β-amino alcohols with high regio- and stereoselectivity.     

Synthesis and properties of bicyclic aziridines,derivatives of triacetoneamine

Bicyclic aziridines, derivatives of 2,2,6,6-tetramethyl-4-piperidone (triacetoneamine), are synthesized, which by acids treatment undergo the N—C(1) or N—C(2) bonds cleavage to form the corresponding pyrrolines, pyrrolidines, and piperidines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 508–511, March, 2007.     

Chiral base promoted enantioselective rearrangement of organophosphorus epoxides

Cinchona alkaloids serve as effective chiral bases for enantioselective rearrangement of 3,4-epoxyphospholane oxides resulting in the formation of P,C-chirogenic 4-hydroxy-2-phospholene derivatives with up to 52% ee. A stereochemical course of the epoxide rearrangement involving anti β-proton abstraction is proposed. 3,4-Epoxy-1-phospholane-borane rearranges to 4-hydroxy-2-phospholene-borane of 55% ee on treatment with sec-BuLi/sparteine base system.     

Stereoselective functionalization of 2-(1-aminoalkyl)aziridines via lithiation of aziridine-borane complexes

Highly selective functionalization of the aziridine ring of (2S,1'S)-2-(1'-aminoalkyl)aziridines 1, through successive formation of aziridine-borane complexes, lithiation, treatment with a variety of electrophiles and final decomplexation is described. The influence of the structure of the starting complexes 2 and of the electrophiles in the stereoselectivity of this process has been studied. Finally, successive double lithiation-electrophile reactions were carried out affording enantiopure 1,2,3,3-tetrasubstituted aziridine-borane complexes with high selectivity.     

The reaction of sulfamic acid derivatives with epoxides

A new method for obtaining N-(b-hydroxyalkyl)sulfamates with 50–95 % yields by the reaction of sulfamic acid derivatives with epoxides is proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1146–1147, June, 1993.