Ueber die Einwirkung von Chloroform auf alkalische Phenolate

Abstract

Ueber die Einwirkung von Chloroform auf alkalische Phenolate. (Aus dem Berl. Univ.-Laborat. CCLXXXVIII; vorgetragen i n der Sitxung vom S. Mai von Hru. Tiemann.) Vor einigen Wochen hat der eine von uns mitgetheilt, dass bei Einwirkung von Chloroform auf stark alkalische Phenoll6sung salicylige Slare entsteht und dass ein Aldehydrest in gleicher Weise auch in das Moleciil anderer Phenole eingefuhrt werden kann. Die Bildung des Salicylaldehyds wird durch die folgende Gleichung veranschaulicht :

Synthesis of salicylaldehydes from phenols via copper-mediated duff reaction

“…The challenge to obtain ortho-selective formylation was to activate the ortho C-atom of the OH group in phenols. Since metal salts are frequently used for promoting ortho-formylation in several other methods [11][12][13][14], a few metal salts (or oxides) were selected for our investigation in the Duff reaction (Scheme 1), and Cu 2 O with oxygen came out to be the best choice for promotion of ortho-selective formylation, the ortho/para selectivity of 2.3:1 and total yield of 80 % were achieved (Table 1, entry 5). All the Cu (II) salts (Table 1, entries 3, 4 and 7), including CuSO 4 , Cu(OAc) 2 , CuO and CuCl 2 , exhibited better performance than their corresponding Cu(I) salts under anaerobic conditions, in terms of both total yields and ortho/para formylation selectivities (Table 1, entries 3, 10, 4 VS 5, and 7 VS 8).…”

“…As listed in Table 3, 1i and 1j (entries 9 and 10), which also bore a carboxyl group on the Scheme 2 Substrate scope phenolic ring, but with the carboxyl group meta-or para-to the hydroxyl group of phenol, the addition of Cu 2 O had no effect on neither selectivity nor total yields. Furthermore, for substrates bearing non-carbonyl group (Table 3, entries [11][12][13][14], addition of Cu 2 O had no impact on both selectivity and formylation yield of Duff reaction. Finally, for substrates bearing carbonyl group but no hydroxyl group, formylation by Duff reaction was not successful (Table 3, entries 15-17).…”

“…Numerous formylation methods were developed to prepare diverse aromatic aldehydes from corresponding phenols [6], such as the Duff reaction [7][8][9], Vilsmeier-Haack reaction [10][11][12], Reimer-Tiemann reaction [13][14][15], Gattermann-Koch reaction [16,17], Gattermann reaction [18,19], Rieche reaction [20][21][22], and paraformaldehyde/MgCl 2 reaction [23,24]. These methods possess their individual advantages, however, low ortho-selectivity of the most of these methods and poor yields sharply limited their application in industry [25].…”

Unusual Rearrangement of Dihalocyclopropanes

“…Faced with what is a potentially new rearrangement, it was necessary to compare it to similar reactions involving either carbene addition, Lewis-acid-induced rearrangement, synthesis of α, β-unsaturated carbonyl compounds and, the Hiyama reaction. Closely related reactions included Reimer-Teimann, Doering-Laflamme, Ciamician-Dennstedt, retro-Griffin and Hiyama-Heatchock reactions, most of which are performed on the aromatic compounds [7][8][9][10][11]. Finally, from a mechanistic standpoint, the obtention of dihalomethylvinyl from dihalocyclopropane should follow one electron mechanism rearrangement pathway suggested by Wang [12].…”

Base-catalyzed reactions of 1-methyl-2-naphthol and its derivatives

“…The Reimer-Tiemann reaction (31) has been a standard method of synthesis of phenolic aldehydes. Ortho and para alkyl substituted phenols yield both phenolic aldehydes and dichlor o-methy 1 cy clohexadienones on treatment with chloro form and aqueous base.…”