Applications of Transition Metals in Hydride Chemistry

Hydrides, essentially mixed hydrides and boron hydrides, are extensively used in organic synthesis as selective (both chemoselective and stereoselective) reagents for the reduction of various functionalities. 

The association of transition metal complexes and of hydrides offer a convenient method for modifying the selectivities (and efficiencies) of the classical hydride reagents. Ill-defined, very active reducing species are formed (transition-metal hydrides ) that promote selectivities quite different from those of the corresponding non-catalyzed reactions. 

Application Matsutake alcohol (a fragrance compound in a Japanese mushroom) is synthesized by reduction of one terminal double bond by LiAlH4—Cp2TiCl2 after protection of an allylic alcohol group as a diisobutylaluminium alkoxide  

Particular transition metal hydrides have found very promising applications in organic reactions, as is shown for example by the hydrozircona-tion reaction, which appears as a remarkable improvement of the classical hydroboration reaction (the high cost of the reagent, however, limits its application in large scale preparations). 

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