CORRELATION BETWEEN THE STRUCTURE AND REACTIVITY OF THE SELENIDE DIHALIDE OF THE NEW REDUCING REAGENT NABH4-R2SEX2 ON THE HIGHLY SELECTIVE REDUCTION OF AMIDES - X-RAY MOLECULAR-STRUCTURE OF BIS-(2-CHLOROETHYL)SELENIUM DICHLORIDE

Treatment of NaBH4 with a diethylselenium dihalide generates borane which reduces amides to the corresponding amines. The reduction abilities of the reductants depend on the structure [that is, trigonal-bipyramidal (TB) or molecular complex (MC)] of 2. The order of the reduction ability is as follows: NaBH4-diiodide 2c > NaBH4-dibromide 2b > dichloride 2a. The reagents, NaBH4-2b and NaBH4-2a, which form TB structures can reduce the tertiary amide with high selectivity, while NaBH4-2c, which forms a molecular complex, reduces primary, secondary and tertiary amides nonselectively.