Sodium borohydride aryl iodides

Vinyl halides add to allylic amines in the presence of Ni(cod)2 where cod=l, 5-cyclooctodine, followed by reduction with sodium borohydride. Aryl iodides add to alkynes using a platinum complex in conjunction with a palladium catalyst. A palladium catalyst has been used alone for the same purpose, and the intramolecular addition of a arene to an aUcene was accomplished with a palladium or a GaCl3 catalyst, " AUcyl iodides add intramolecularly to aUcenes with a titanium catalyst, or to alkynes using indium metal and additives. The latter cyclization of aryl iodides to alkenes was accomplished with indium and iodine or with Sml2. " ... 

The difference in the reactivity of benzylic versus aromatic halogens makes it possible to reduce the former ones preferentially. Lithium aluminum hydride replaced only the benzylic bromine by hydrogen in 2-bromomethyl-3-chloro-naphthalene (yield 75%) [540]. Sodium borohydride in diglyme reduces, as a rule, benzylic halides but not aromatic halides (except for some iodo derivatives) [505, 541]. Lithium aluminum hydride hydrogenolyzes benzyl halides and aryl bromides and iodides. Aryl chlorides and especially fluorides are quite resistant [540,542], However, in polyfluorinated aromatics, because of the very low electron density of the ring, even fluorine was replaced by hydrogen using lithium aluminum hydride [543]. 

Arene(tricarbonyl)chromium complexes, 19 Nickel boride, 197 to trans-alkenes Chromium(II) sulfate, 84 of anhydrides to lactones Tetrachlorotris[bis(l,4-diphenyl-phosphine)butane]diruthenium, 288 of aromatic rings Palladium catalysts, 230 Raney nickel, 265 Sodium borohydride-1,3-Dicyano-benzene, 279 of aryl halides to arenes Palladium on carbon, 230 of benzyl ethers to alcohols Palladium catalysts, 230 of carboxylic acids to aldehydes Vilsmeier reagent, 341 of epoxides to alcohols Samarium(II) iodide, 270 Sodium hydride-Sodium /-amyloxide-Nickel(II) chloride, 281 Sodium hydride-Sodium /-amyloxide-Zinc chloride, 281 of esters to alcohols Sodium borohydride, 278 of imines and related compounds Arene(tricarbonyl)chromium complexes, 19... 

Aryl and vinyl bromides and iodides have been employed most commonly, with 1-5 mol% Pd , and reaction temperatures ranging from ambient to 125 °C (equation 11). The Pd catalyst can be Pd(Pli3P)4 or the Pd species produced by in situ reduction of Pd. The alkene itself can serve as the reducing agent for Pd but the catalyst can also be produced by deliberate addition of a reducing agent, such as sodium borohydride, formic acid, or hydrazine. ... 

Apart from sodium borohydride, which is frequently used in water or water-alcohol mixtures to reduce ketones or aldehydes selectively, water is rarely used as the solvent in reductions, because of incompatibility with most reducing agents. However, samarium iodide reduction of ketones, as well as alkyl and aryl iodides is accelerated in water [99]. Likewise, the a-deoxygenation of unprotected aldonolac-tones is efficient when the SmI2-tetrahydrofuran-water system is used [100],... 

Reduction of alkyl and aryl bromides and iodides by sodium borohydride PE- SnBuzCl PE- SnPh2Cl Sn 162... 

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