Diastereo- and Enantioselective Synthesis of trans-2-Amino-Cycloalkane-1-Carboxylic Acids via Intramolecular Tandem Michael-Addition/α-Alkylation Using TMS-SAMP as Chiral Equivalent of Ammonia

All articles of this category trans -2-amino cyclopentane-, cyclohexane- and cycloheptane-1-carboxylic acids of high diastereo- and enantiomeric purity ( de ≥ 96-98%, ee ≥ 98%) are prepared utilizing the stereoselective conjugate addition of lithiated ( S )-(-)-2-methoxymethyl-1-trimethylsilylamino-pyrrolidine (TMS-SAMP) to ω -halide substituted α , β -unsaturated enoates followed by subsequent ring closure of the intermediate ester enolate (MIRC-reaction). The auxiliary is removed by reductive N-N bond cleavage. β-amino acids - Michael initiated ring closure - TMS-SAMP - nitrogen-nucleophile - asymmetric synthesis