Enantioselektive 1,4-Additionen von metallorganischen Verbindungen an konjugierte Systeme im chiralen Medium DDB

Enantioselective 1,4-additions of organometallic compounds to conjugated systems in the chiral medium DDB

1 DDB = 1,4-Dimethylamino-2,3-dimethoxybutan (= 2,3-Dimethoxy-N,N,N′,N′-tetramethyl-1,4-butandiamin).

The chiral methoxyamine DDB is used as a cosolvent to add achiral Li-, Cu-, and Zn-organic compounds enantioselectively to prochiral β-carbon atoms of α, β-unsaturated aldehydes, ketones, nitro compounds and ketene-thioacetals (Tables 1 and 2). The selectivity generally ranges from 55:45 to 63:27, in one case ( 9b ) an enantiomeric excess of 43% was obtained.