And Birch reduction

The use of reducing metals nowadays is mainly restricted to acyloin and pinacol coupling reactions (see p. 53f.) and Birch reductions of arenes (A.A. Akhrcm, 1972 see p. 103f.) and activated C—C multiple bonds (see p. 103f.). 

Select one compound from (37) - (40) for synthesis by each of the methods of this chapter Robinson annelation, Diels-Alder reaction, total reduction of aromatics, and Birch reduction. 

Liquefaction Solvents. The solvents used in the present study are listed in Tables 2 and 3. Alkylated and hydrogenated pyrenes were synthesized by Friedel-Crafts and Birch reduction, respectively. Details have ° been described in another place (9). 

Q Predict the products of oxidation and reduction of the aromatic ring, including hydrogenation, chlorination, and Birch reduction. Predict the products of the oxidation of phenols. 

With anilines, it is impossible to stop the isomerization taking place during the reaction, and Birch reduction always gives conjugated enamines. 

Benzyl ethers are Cleaved urider both hydrogenation and Birch reduction conditions. Both methods are used in the deprotection of benzyl-protecteo alcohols. The by-product is toluene ... 

Aromatic ketones represent a rather special case in dissolving metal reductions. Under many conditions pinacol formation is the predominent reaction path (see Volume 3, Chapter 2.6). Also, the reduction potentials of aromatic carbonyl compounds are approximately 1 V less negative than their aliphatic counterparts. The reductions of aromatic ketones by metals in ammonia are further complicated by the fact that hydrogenolysis of the carbon-oxygen bond can take place (Chapter 1.13, this volume) and Birch reduction may intervene (Chapter 3.4, this volume). 

Reduction of an alkyne. The best-known reactions of this type are Lindlar reduction, the McMurry reaction and Birch reduction. 

Kaiser, E. M. Comparison of methods using lithium/amine and Birch reduction systems. Synthesis 1972, 391-415. 

With the related 6-methoxy compound shown the cyclisation to a morphinan with hydrochloric acid proceeded to the unwanted product C in 37% yield and the desired one in only a 3% yield (ref. 179). The same precursor, synthesised from 2-(3-methoxyphenyl)ethylamine and 3,4-dimethoxyphenylacetic acid by amide formation and ring closure by the Bischler-Napieralski cyclisation, followed by reduction, methylation and Birch reduction, was used by others with similar results (ref. 180). The route constitutes a synthesis of morphine by the use of the final steps of earlier work (refe. 169,171), albeit in low yield, although in considerably fewer steps than the earlier syntheses. 

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