| Abstract
| - Treatment of a range of N-sulfonyl (Ts and SES) imines derived from aromatic, heteroaromatic,aliphatic, and unsaturated aldehydes with trimethylsilydiazomethane gave C-silylaziridines in goodyield (32−83%) and with high diastereoselectivity in favor of the cis product (80:20−100:0). Incontrast, an α-imino ester gave predominantly the trans-aziridine (89:11) in high yield (91%). Thesynthetic potential of C-silylaziridines was investigated. Treatment with F- (tetrabutylammoniumtriphenyldifluorosilicate was used) in the presence of aldehydes gave the α-hydroxyaziridines inhigh yield and high diastereoselectivity (86:14−98:2) for the newly created stereogenic center.Complete retention of configuration was observed in the substitution of the silyl group withelectrophiles in all cases. Trapping with deuterium (using CDCl3 as electrophile) was also successful,but trapping with phosphate [using ClP(O)(OPh)2] and acetate (using Ac2O) was unsuccessful. Inthese latter cases ring opening by chloride and acetate, respectively, was observed. Further ring-opening reactions were effected using azide and thiolate nucleophiles and in all cases completeregioselectivity in favor of attack at the silyl-bearing carbon occurred. Complete regioselectivitywas also observed in the carbonylative ring expansion using Co2(CO)8 to give a β-lactam. Treatmentof cis-1-tosyl-2-phenyl/butyl-3-trimethylsilylaziridines with n-BuLi and subsequent quenching withMeI followed completely different pathways, depending on the 2-substituent. In the case of the2-phenylaziridine, metalation was initiated α to the phenyl group and led finally to a fused tricyclicadduct with four stereogenic centers as a single diastereoisomer. In the case of the 2-butylaziridine,metalation occurred α to the silyl group and led to a trisubstituted silylaziridine, probably via anazirine intermediate.
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