Diastereocontrolled Monoprotodeboronation of β-Sulfinimido gem-Bis(boronates): A General and Stereoselective Route to α,β-Disubstituted β-Aminoalkylboronates.

摘要: β-Aminoalkylboronic acids are bioisosteres of the pharmaceutically important class β-amino but few stereoselective methods exist for their preparation. The 1,2-addition lithiated 1,1-diborylalkanes onto chiral N-tert-butanesulfinyl aldimines produces β-sulfinimido gem-bis(boronates) in good to excellent yields with high diastereoselectivity. optimized conditions involve use rubidium fluoride and water, compatible functionalized alkyl, aryl, alkenyl, alkynyl substituents. Under these conditions, geminal quaternary alkyl bis(pinacolatoboryl) intermediates undergo a highly diastereoselective monoprotodeboronation afford wide range syn-α,β-disubstituted β-aminoalkylboronates. This novel application protodeboronation chemistry was shown result from kinetically controlled, diastereotopic-group-selective B-C bond protolysis dictated by configuration adjacent stereogenic C-N center. Facile acidic cleavage sulfinimide auxiliary free aminoboronates enantiomeric purity.