O 2 ‐Assisted Four‐Component Reaction of Vinyl Magnesium Bromide with Chiral N ‐ tert ‐Butanesulfinyl Imines To Form syn ‐1,3‐Amino Alcohols

An O 2 ‐assisted, four‐component reaction has been developed to synthesize a wide range of syn ‐1,3‐amino alcohols in one step. The reaction proceeds by oxygenation of vinyl magnesium bromide ( component‐I ) with O 2 ( component‐II ) to give a magnesium enolate of acetaldehyde, which undergoes addition to a chiral N ‐ tert ‐butanesulfinyl imine ( component‐III ) followed by a sequential addition with excess vinyl magnesium bromide ( component‐IV ). The approach allows diastereoselective synthesis of anti / syn ‐ and syn / syn ‐3‐amino‐1,5‐diols in good yields with high diastereoselectivity. The method was illustrated in an efficient, four‐step synthesis of piperidine alkaloid (−)‐2′‐ epi ‐ethylnorlobelol.