Stereoselective Synthesis of Enantioenriched Acetylenic 1,2-Amino Alcohols

The stereoselective synthesis of enantioenriched ANTI- and SYN-4-aminoalk-1-yn-3-ols is described. Initial reaction of racemic 3-(methoxymethoxy)allenylzinc with enantiopure Ellman’s ( S S )-( TERT-butylsulfinyl)imines was shown to give straightforward and highly stereoselective access to ANTI-( S S ,3 S,4 R)-3-(methoxy-methoxy)-4-sulfinamidoalk-1-ynes. Upon treatment with dry methanolic hydrochloric acid at reflux, the latter led to the corresponding enantioenriched ANTI-(3 S,4 R)-4-aminoalk-1-yn-3-ols. Regarding the SYN-diastereomeric (3 R,4 R)-4-aminoalk-1-yn-3-ols, they were obtained by ring opening of the corresponding CIS- N-( TERT-butylsulfinyl)aziridines by water under acidic conditions.