Scope and limitations of diastereoselective aziridination reactions using stabilised ammonium ylides or α-bromo carbonyl nucleophiles
作者:Stefan Aichhorn、Guddeangadi N. Gururaja、Michael Reisinger、Mario Waser
DOI:10.1039/c3ra40429c
日期:——
The applicability of easily available ammonium salts to access aziridines via an ammonium ylide pathway was carefully investigated and compared with classical aza-Darzens approaches using α-bromo carbonyl nucleophiles. Whereas amide-stabilised ammonium ylides could be successfully reacted with aromatic aldimines to obtain the corresponding trans-aziridines in good yields and with high diastereoselectivities, α-bromo amides failed. In sharp contrast, acetophenone-based ylides did not give any aziridines while in this specific case α-bromo acetophenone derivatives gave the corresponding cis-aziridines in high yields and with excellent diastereoselectivities under optimised conditions.
A novelsyntheticmethod of ketodiphenylselenonium ylide from alkynylselenonium salt is described. A reaction of alkynylselenonium salt, hydroxide ion, and aldehyde in the presence of silver triflate and triethylamine gave oxiranylketones just as a trans-isomer in moderate to good yields, whereas benzoyl aziridine derivatives were obtained from the reaction with sodium p-toluenesulfonamide instead
3-Substituted 2-Acyl-1-sulfonylaziridines from the Reaction of Triphenylbismuthonium 2-Oxoalkylides and N-Sulfonylaldimines. Reversal of the cis/trans-Isomer Ratios Depending on Base and Additive