Hydrogen transfer reagents asymmetric reduction

IPC)2BC1 (6.64) also transfers 3-hydrogen and librates 1 equiv. of a-pinene. The reagent is best used for the asymmetric reduction of arylalkyl ketones, a-t-alkyl ketones and a-halo ketones. 

Oishi T, Akita H 0983) Asymmetric reduction by yeasts. Formation of optically active synthons having two chiral centers useful for natural product synthesis. J Synth Org Chem Jpn 41 1031-1043 Okamoto T, Ohno A, Oka S (1977a) Reaction of N-propyl-1,4-dihydro-nicotinamide with ferricyanide ion. J Chem Soc Chem Commun 181-182 Okamoto T, Ohno A, Oka S (1977b) Alkali-metal ion acceleration of the electron-transfer reaction between N-propyl-1,4-dihydronicotinamide and ferricyanide ion. J Chem Soc Chem Commun 784-785 Okamoto T, Ohno A, Oka S (1979) Reduction of transition-metal salts by N-propyl-1,4-dihydronicotinamide. Bull Chem Soc Jpn 52 3745-3746 Ono N, Tamura R, Kaji A (1980) 1-Benzyl-1,4-dihydronicotinamide as a reagent for replacing aliphatic nitro groups by hydrogen An... 

Fig. 10.24. Asymmetric carbonyl group reduction with Alpine-Borane (preparation Figure 3.27 for the "parachute-like" notation of the 9-BBN part of this reagent see Figure 3.21). The hydrogen atom that is in the cis-position to the boron atom (which applies to both ft- and /T-H) and that after removal of the reducing agent leaves behind a tri- instead of a disubstituted C=C double bond (which applies to ft-, but not / -H) is transferred as a hydride equivalent. In regard to the reduction product depicted in the top row, the designation S of the configuration relates to the aryl-substituted and R to the Rtert-substituted propargylic alcohol.

Precursor of Useful Chiral Ligands. OPEN is widely used for the preparation of chiral ligands. Organometallic compounds with these ligands act as useful reagents or catalysts in asymmetric induction reactions such as dihydroxylation of olefins, transfer hydrogenation of ketones and imines, Diels-Alder and aldol reactions, desymmetrization of meso-diols to produce chiral oxazolidinones, epoxidation of simple olefins, benzylic hydroxylation, and borohydride reduction of ketones, imines, and a,p-unsaturated carboxylates. ... 

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