Borohydride exchange resin

See Wallace, O.B. Springer, D.M. Tetrahedron Lett., 1998, 39, 2693 for cleavage of thiol esters to thiols with NaSMe in methanol and Choi, J. Yoon, N.M. Synth. Commun., 1995, 25, 2655 for borohydride exchange resin-Pd(OAc)2 reductive cleavage of thiol esters to thiols. 

COOH or NHCOCH3, for example, 2-phenyl-l-butene. Enantioselective reduction of certain alkenes has also been achieved by reducing with baker s yeast. Hydrogenation with Ni2B on borohydride exchange resin (BER) has also been... 

Triple bonds can also be selectively reduced to double bonds with DIBAL-H, " with activated zinc (see 12-36), with hydrogen and Bi2B-borohydride exchange resin, ° or (internal triple bonds only) with alkali metals (Na, Li) in liquid ammonia or a low-molecular-weight amine.Terminal alkynes are not reduced by the Na—NH3 procedure because they are converted to acetylide ions under these conditions. However, terminal triple bonds can be reduced to double bonds by the... 

NaBH4—BiCl3, borohydride exchange resin, (BER)—CuS04, Smla, and See 16-23 for methods of reducing C=0 bonds in the presence of... 

Pr)4, " borohydride-exchange resin,and formic acid. When the last is used, the process is called the Wallach reaction. Conjugated aldehydes are converted to alkenyl-amines with the amine/silica gel followed by reduction with zinc borohydride.In the particular case where primary or secondary amines are reductively methylated with formaldehyde and formic acid, the method is called the Esch-weiler-Clarke procedure. It is possible to use ammonium (or amine) salts of formic acid, " or formamides, as a substitute for the Wallach conditions. This method is called the Leuckart reaction,and in this case the products obtained are often the N-formyl derivatives of the amines instead of the free amines. Primary and secondary amines can be iV-ethylated (e.g., ArNHR ArNREt) by treatment with NaBH4 in acetic acid. Aldehydes react with aniline in the presence of Mont-morillonite KIO clay and microwaves to give the amine. Formaldehyde with formic acid converts secondary amines to the N-methyl derivative with microwave irradiation. 

BER = borohydride exchange resin Choi, J. Yoon. N.M. Svnth. Commun., 1995, 25, 2655... 

Sulfur transfer can also occur from sulfurated borohydride exchange resin <2001TL6741> the reaction proceeds in methanol at ambient temperature rapidly (<5min) and in high yield (91%). From l,4-di(acetylthio)butane, 1,2-dithiane can be obtained by a one-pot synthesis in excellent yield (98%) using BuzSn(OMe)2, FeCls, and a catalytic amount of CsF as a promoter in THF solution <1990TL3595>. 

Fig. 9 Nickel-catalyzed radical addition reactions mediated by borohydride exchange resins (BER)...

Borabicyclo[3.3.1]nonane Borohydride exchange resin 2/ ,3S-2,2 -te-(diphenylphosphino)-1,1 -binapthyl... 

Yanada et al. synthesized a new selenide exchange resin 78 by treatment of borohydride exchange resin (BER) with selenium. The subsequent reaction with alkyl halides or tosylates gives dialkyl selenides 79 selectively in a high yield (Scheme 50) [95]. 

---