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Catalytic Asymmetric Aziridination of Enol Derivatives in the Presence of Chiral Copper Complexes to give Optically Active α‐Amino Ketones
Author(s) -
Adam Waldemar,
Roschmann Konrad Johann,
SahaMöller Chantu Ranjan
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(200002)2000:3<557::aid-ejoc557>3.0.co;2-b
Subject(s) - chemistry , enol , iodobenzene , enantioselective synthesis , steric effects , catalysis , ligand (biochemistry) , medicinal chemistry , asymmetric induction , organic chemistry , stereochemistry , biochemistry , receptor
A series of acyclic and cyclic enol derivatives 1 has been transformed into the corresponding α‐amino‐functionalized ketones 2 by means of enantioselective catalytic aziridination with chiral Cu complexes, prepared in situ from [Cu(MeCN)4]PF 6 and the optically active ligands 3 , by using ( N ‐tosylimino)iodobenzene (PhINTs) as a nitrogen source. The best enantioselectivities ( ee values of up to 52%) have been achieved for the electronically deactivated enol acetate 1aδ , but the incorporation of steric bulk and the substitution pattern at the enol double bond do not improve the ee values. The cyclic substrates react considerably less readily (only up to 45% conversion) compared to their acyclic counterparts (complete consumption). A transition structure is suggested for the asymmetric Cu‐catalyzed aziridination of the enol acetate 1aδ in the presence of the chiral ligand 3b that could account for the sense of the ( R )‐configured product 2a .