Aziridine substitution

Sharpless asymmetric dihydroxylation procedure was applied to the synthesis of the side chain of azinomycin A (equation 26)43. Horner-Emmons condensation of phospho-nate 36 with a /J-aziridine substituted acrolein afforded dehydroamino acid diene 37. Treatment of the diene with catalytic amounts of an osmium reagent and dihydroquini-dine (DHQD) p-chlorobenzoate resulted in asymmetric dihydroxylation, producing diol 38. Diol 38 was further converted to the naphthyl ester. 

Garner et al. (90,320) used aziridines substituted with Oppolzer s sultam as azomethine ylide precursors. The azomethine ylide generated from 206 added to various electron-dehcient alkenes, such as dimethyl maleate, A-phenylmalei-mide, and methyl acrylate, giving the 1,3-dipolar cycloaddition product in good yields and up to 82% de (for A-phenylmaleimide). They also used familiar azomethine ylides formed by imine tautomerization (320). Aziridines such as 207 have also been used as precursors for the chiral azomethine ylides, but in reactions with vinylene carbonates, relatively low de values were obtained (Scheme 12.59) (92). 

The reactions of N-substituted iminophosphoranes 5 with alkyl or aryl isocyanates proceed under mild conditions to give aziridin substituted carbodiimides 6 (R = H, Ph R = Me, Ph, a-naphthyl), which are only observed in solution, and their yield is... 

Quinze, K. Laurent, A. Mison, P. Synthesis of secondary aziridines substituted with a trifluoromethyl group. J. Fluorine Chem. 1989, 44, 211. 

Aziridines.—Reviews on general methods of aziridine synthesis and the preparation and properties of aziridine-substituted fatty acids have appeared. 

Studied using chloride-ion-selective electrodes in a buffered medium. Base-catalysed cyclization of the hydroxy amino-acid tosylate (215) provides a synthetic route to aziridine-substituted peptides (216). The synthesis of... 

---