With NaBHj

Alkenes of the form RCH=CHR and RR C=CH2 add to nitriles in the presence of mercuric nitrate to give, after treatment with NaBHj, the same amides that would be obtained by the Ritter reaction. This method has the advantage of avoiding strong acids. 

The incorporation of tin considerably changed the catalyhc performance for acetophenone hydrogenahon, both in terms of achvity and selectivity. Both for PtSn-BM and for PtSn-OM, the initial reaction rate, ri, decreased with respect to that of Pt/SiOj (156, 78 and 434 xmols gi for PtSn-BM, PtSn-OM and Pt/SiOj, respectively). However, the selectivity to PE increased for both hn-modified systems. For the PtSn-BM catalyst (Figure 6.14b), the major product obtained is PE, with 93% selectivity at 100% conversion. The most interesting result was obtained with the PtSn-OM catalyst (Figure 6.14c) selectivity to PE exceeds 99% (equal to the chemical reduction with NaBHJ, and no subsequent hydrogenation to CHE is observed. 

Probtom 13.14 Reduction of HjC=CHCHO with NaBHj gives a product different from that of catalytic hydrogenation (H2/Ni). What are the products ... 

Zolmitriptan (2, BW-311C90) was discovered by Wellcome in the United Kingdom and then transferred to AstraZeneca upon the acquisition of Wellcome by Glaxo (now GlaxoSmithKline). The synthesis began with 4-nitro-L-phenylalanine (29), which was converted to the methyl ester and then reduced with NaBHj to give the amino alcohol (Scheme 8). ° Oxazolidinone 30 was formed by treating the amino alcohol... 

Reduction of pyridinium salts. Pyridinium salts are reduced by 1, mainly to 1,4-dihydropyridines. The yield is generally higher than that obtained with NaBHj or Na.SA-Examples ... 

Mixed acetals. A variety of functionalized mixed acetals can be prepared by acc-toxymercuration of a mixture of a vinyl ether and an alcohol followed by demercuration with Na,CS, (10, 369- 570) or, in simple systems, with NaBHj. Unsaturated alcohols can be used, and the vinyl ether can contain various functional groups, although not a cyano group. 

Nitroarenes can be effectively determined by RP-HPLC-FLD after reduction to the corresponding PAA. Reduction with NaHS was found to be more efficient than with NaBHj/CuCL. The method was applied to determination of 2-nitrofluorene and 1-nitropyrene, which were converted to 2-fluorenylamine (10b) and 1-pyrenamine (13), respectively, and were found to be at ca 5 ppm levels in dust collected in the Upper Silesia region202. 

Z,E)-l,3-Dienol ethers reduction with NaBHj-NiiC... 

Dimethoxy-2-methylphenol (108) was oxidized with DDQ in MeOH at 0°C to afford in 63% yield 2-methyl-4,4,5-trimethoxycyclohexa-2,5-dienone (518), which reacted with 1,2-dimethylcyclopentene (519) in MeN02-CH2Cl2 containing stannic chloride to yield a mixture of two adducts. This mixture was reduced directly with NaBHj in MeOH to give a separable mixture of 520 and 521 in 10% overall yield. The former was smoothly converted to the target molecule 517 (Scheme 98). 

Identity in environment unoertain (if hydride, species identified after derivatization with NaBHJ. Counterion unknown. 

Reaction with NaBHj/SbPh, 8, 4.8.4.4.1 C3 H3oCl3PjPdSn PdCl(SnCl,)(PPh,)2 Monohydride precursor 16, 14.3.2.2 (table)... 

Reduction of ketones (supported afforded reverse diastcreosclectivity as compared with NaBHJ.2l2... 

Trialkyl borohydrides such as Lithium Tri-s-butylborohydride and Potassium Tri-s-butylborohydride are superior reagents for the chemoselective 1,4-reduction of enones. On the other hand, 1,2-reduction can be obtained by using NaBHj in the mixed solvent MeOH-THF (1 9), or with NaBHj in combination with CeCH or other lanthanide salts. ... 

The combination of NaBILj and CeCH used for chemoselec-tive or diastereoselective reduction of ketones (see Original Commentary and Hirst Update) could also be employed for the reduction of carboxylic esters. In the presence of a catalytic amount of CeCl3-7H20 (1 mol%), various methyl carboxylates were reduced to alcohols with NaBHj in EtOH at ambient temperature in good to high yields (75-95%). 

Regioselective reduction of aryl-substituted epoxides with NaBHj is catalyzed by PdCl2 in the presence of moist alumina (H2O content, 19 wt%) in hexane. The selectivity in reduction of aryl-substituted epoxides was the same as with NaBILj and diborane. In addition, the alumina can be easily recovered and reused without further treatment. 

Some of substrates required for this study were prepared in mechanochemical conditions ethyl 3-(furan-2-yl)-3-hydroxypropanoate was prepared by Reformatsky reaction (chapter Carbon-Carbon Bond- Forming Reactions), while reduction of 2-acetylbenzofuran 57 was carried out with NaBHj (Scheme 6.20). Reduction of aldehyde 54 in planetary ball mill (agate beaker and balls) afforded alcohol 57 in high yield while the presence of choline chloride gives better yield, reduction of 5-hydroxymethylfurfural 56 without choline chloride was sluggish. 

It has been reported that reduction of the carbonyl groups of tetrahydroxy-ketocalix[4]arene 21 with NaBHj in 2-propanol, followed by heating to reflux the product in Me0H/H2S04, affords an octahydroxycalix[4]arene [17a]. However, a recent reinvestigation of the reaction indicated that after the work-up reported in the literature, the product of the reaction consist of an isomeric mixture of the tetrahydroxycalix[4]arene derivative 22, where all bridges are monosubstituted by a methoxy group (Eq. 4.15) [26]. 

Homer-Wadsworth-Emons reaction (HWE reaction) of triethyl 2-fluorophos-ponoacetate 12 with an aldehyde stereoselectively yields an ( )-a-fluoro-a,p-unsaturated ester 13 [30], and it has been used to synthesize a fluorinated analog of natural compounds [31-33], Nagao et al. reported recently that the (Z)-isomer of a-fluoro-a,p-unsaturated ester 13 can be prepared stereoselectively by the reduction of triethyl 2-acyl-2-fluoro-2-phophonoacetate 14 with NaBHj at low temperature [34]. As the starting compound 14 can be prepared by the acylation of 12, both ( )- and (Z)-13 can be prepared from 12 stereoselectively [34] (Table 1). 

A new general synthesis of 3-substituted derivatives has been reported (99MC13) (Scheme 9). Thus, the nitro group of furoxan 27 underwent a facile hydride replacement on treatment with NaBHj in EtOH to give 3-monosubstituted furoxans 23. The result of this reaction is independent of the nature of R. 

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