The lithium disiamylethoxyborohydride (LSEBH) were characterized by hydride analyses. t-Buthyllithium with disiamylethoxyborane possessing steric requirements has been synthesized. This reaction occurs rapidly, even at -78 ℃. Lithium disiamylethoxyborohydride (LSEBH) completely reduces the acetophenone to corresponding alcohol in 99% yield.