Lithium benzamide

Mukaiyama developed a variety of catalytic carbon-carbon bond-forming reactions with the use of trimethylsilyl nucleophiles in the presence of simple lithium Lewis-base catalysts, such as lithium acetate, lithium pyrro-lidone, lithium succinimide, lithium benzamide, lithium diphenylamide, and lithium benzyloxide (Scheme 2.1). For example, the Mukaiyama aldol... 

Less traditional Lewis acid catalysts have also been employed to mediate additions of silyl ketene thioacetals to imines and hy-drazones, including scandium(III) triflate and bismuth(III) triflate. In a significant recent advance, Mukaiyama and coworkers reported Lewis base catalyzed additions of the trimethylsilyl congener of the title reagent to iV-sulfonyl aldimines (eq 18). The reaction is tolerant of water and competent Lewis base activators include readily obtained salts such as lithium acetate and lithium benzamide. 

It has been shown that, in the presence of lithium diethylamide at —70 °C, bromoben-zoic acids form arynes which may react with arylacetonitriles to yield, predominantly, 2-cyanobenzoic acids. The reaction of alkyl and aryl isocyanides with benzyne may yield benzamide derivatives, showing their ability to act as charge-reversed equivalents to isocyanates. The generation and cyclization of a benzyne-tethered alkyllithium have been reported, and lead to a convenient synthetic route for 4-substituted indans. ... 

Benzamides 565 without any substituent at the para position reacted with lithium and a catalytic amount of naphthalene under Barbier-type reaction conditions (in the presence of a carbonyl compound) in THF at —78 °C to give, after hydrolysis, the corresponding dearomatized products 566 (Scheme 151). When 567 was used as starting material with a 4-ferf-butyl group in p-position, and using 3-pentanone as electrophile and under the same reaction conditions, the fraw -product 568 was the only one isolated . 

The iodo benzamide derivative of pyrrolo[2,l-c][l,4]benzodiazepine 367 (R = I, Scheme 75, Section 5.1.1) reacts with bis(tributyl)tin, lithium chloride and tetrakis(triphenylphosphine) palladium(O) in refluxing dioxane to yield the stannyl derivative 370. The latter couples with substituted aryl bromides in the presence of... 

Die Reduktion von Benzhydroxamstiure mit Lithium-alanat in Tetrahydrofuran ergibt Benzylamin in 50% Ausbeute, wahrend die gleiche Reduktion des O-Benzoyl-Derivates von Benzhydroxamsaure, namlich N-Benzoyloxy-benzamid, 80% Ausbeute an Benzylamin neben 90% Ausbeute an Benzylalkohol ergibt3. 

These critical values differ from solvent to solvent. With the solvents most fully investigated, sulphuric acid for poly-(p-phenylene terephthalamide) and dimethyl acetamide/lithium chloride for poly (p-benzamide), there are also critical values of solvent composition the sulphuric acid must exceed a critical strength, the lithium chloride in the dimethyl acetamide must exceed a critical concentration. The critical values are, of course, interdependent rather than absolute. Diagrams that display some of the critical values for the two systems cited have been published in patents10,1 l Figures 3 and 4 illustrate the type of information available. 

Fig. 3. Phase diagram for solutions of poly-p-benzamide in dimethyl acetamide/lithium chloride I0). Polymer inherent viscosity 1.18...

Fig. 5. Viscosity of poly-/>-benzamide solutions in dimethyl acetamide/lithium chloride as a function of concentration and intrinsic viscosity 29). Values of intrinsic viscosity are (1) 0.47, (2) 1.12, (3) 1.68, (4) 2.96...

Attempts to induce asymmetry in the cyclisation of 57 using the chiral lithium amides, which had worked well with simple benzamides, were frustrated by the inherent chirality, at low temperature, of the naphthamide itself. This feature is common to all 2-substituted tertiary aromatic amides, which may become atropisomeric at low temperature due to slow rotation about the Ar-CO bond.48 We therefore sought to... 

As shown by the last reaction in Scheme 5.23, the metalation of benzamides is complicated by several potential side reactions (Scheme 5.24). Thus, benzamides can also undergo ortho-metalation [181, 217-222] or metalation at benzylic positions [223-225], Ortho-metalation seems to be promoted by additives such as TMEDA, and benzylic metalation can be performed selectively with lithium amide bases [217,224], which are often not sufficiently basic to mediate ortho- or a-amino metalation. If deprotonation of the CH-N group succeeds, the resulting product might also undergo cydization by intramolecular attack at the arene [214, 216] (see also Ref. [226] and Scheme 5.27) instead of reacting intermolecularly with an electrophile. That this cydization occurs, despite the loss of aromatidty, shows how reactive these intermediates are. 

Treatment of Af-BOC benzaldimines 347 with lithium w-chloroperoxybenzoate afforded the corresponding A -BOC oxaziridines 348 in 36-79% yields <1995TL1439>. Use of MCPBA resulted in formation of A -BOC benzamides, and Oxone gave no reaction. 

Phenylpropene oxide is selectively reduced in the presence of rra 5-stilbene oxide even with an excess amount of sodium borohydride (equation 16), and a similar system using lithium borohydride (LiBHa) also shows selective reduction of a styrene oxide in the presence of a benzamide. ... 

Two groups report the addition of metalated benzamides to aldehyde carbonyls. The methods differ in the metal. Lithiated diethylamides must be transmetalated with MgBr2 before addition to the aldehyde, but p-aminoamides react similarly as the lithium derivative. Following addition, the hydroxyamide is hydrolyzed to afford phthalides in moderate overall yield (Scheme 11). 

Anionic bridged bis(amidinate) lithium lanthanide complexes have been found to be efficient catalysts for the amidahon of aldehydes with amines under mild conditions (Scheme 56). The achvity was found to follow the order of yttrium < neodymium < europium ytterbium. The catalysts are available for the formahon of benzamides derived from pyrrolidine, piperidine, and morpholine with good to excellent yields. In comparison with the corresponding neutral complexes, the anionic complexes showed higher achvity and a wider range of scope for the amines. A cooperation of the lanthanide and lithium metals in this process was proposed to contribute to the high activity of these catalysts [66,67]. 

Treatment of 75 with lithium acetylide ethylenediamine complex afforded the acetylene derivative 78 (85%), which was transformed into the vinyl alcohol 79 by partial hydrogenation using Lindlar catalyst. Employing the Mitsunobu reaction, compound 79 was transformed into the phthalimide 80, which was converted into the benzamide 82 (64%) via the primary amine 81 by sequential deacylation and benzoylation. When the... 

The key step in a new acridone (123) synthesis involves the oxidative coupling of the anilidocuprate generated from lithium anilide and copper(I)cyanide with the lithio derivative of a tertiary benzamide (121). The anthranilamide (122) formed is subsequently cyclised by treatment with heptafluorobutyric acid. 

Tertiary benzamides can be efficiently metallated at the ortho position by Bu Li at -78 °C in the presence of TMEDA the aryl-lithium derivatives thus produced react well with a range of electrophiles. Of particular relevance to this section of the Report is their reaction with ketones leading to the phthalide derivatives (56). 3-Aryl-3-methylphthalides (57) are available from a Friedel-Crafts reaction between o-acetylbenzoyl chloride and arenes using stannic chloride as Lewis acid. ° A total synthesis of the phthalide derivative iso-ochracinic acid (58) has been reported. ... 

Aryl-lithiums. Details of the ort/io-lithiation of tertiary benzamides have appeared.In a popular year for syntheses of rosefuran, one such synthesis has involved the sequence shown in Scheme 5, and proceeds in 71% overall yield." ... 

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