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 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.