N-(hydroxyalkyl)pyrazoles and borane formed boric ester complex, in which the remaining borane was stabilized by the adjacent nitrogen of thr pyrazole ring. The borane complex derived from the chiral pyrazoles such as 3-phenyl-l-menthopyrazole reduced p-methylacetophenone (21) enantioselectively. When (2′S)-2-(2′-phenyl-2′-hydroxyethyl)-3-phenyl-l-menthopyrazole ((2′S)-10b) was used, 21 was reduced into (