Sodium tert-butoxide

Exposure of compound 16, a substance that can be obtained in a straightforward manner from glycine, to sodium tert-butoxide furnishes an enolate that undergoes conversion to 8 upon treatment with terf-butyl formate. It was anticipated that the phthalimido and tert-butyl ester protecting groups in 8 could be removed easily and selectively under anhydrous conditions at a later stage in the synthesis. 

Dimethyl 3,4-dimethyl-2-methylene-3-azabicyclo[4.1.0]hept-4-ene-l,5-dicarboxylate (26), formed by the action of sodium tert-butoxide on dimethyl 4-(chloromethyl)-l,2,6-trimethyl-l,4-dihydropyridine-3,5-dicarboxylate, undergoes rapid rearrangement in the presence of acid to give dimethyl l,2,7-trimethyl-l//-azepine-3,6-dicarboxylate (27).126... 

Caubere et al. [63, 64] treated 32a with sodium amide-sodium tert-butoxide (NaNH2-NaOtBu) in tetrahydrofuran (THF) in the presence of secondary amines and obtained enamines. Analogously, the corresponding thioenol ethers were formed from 32a and sodium amide-sodium thiolate in the presence or absence of NaOtBu. It was shown, however, that cyclohexyne rather than 6 is the decisive intermediate en route to the enamines as well as the thioenol ethers [63b, 64], As already mentioned above, the enol ether 41 arises inter alia from 32b and KOtBu in DMSO. The best yield (47%) was obtained in refluxing THF (Scheme 6.11) [60],... 

See Butyllithium, Sodium tert. butoxide Dimethyl sulfide... 

Sodium tert. butoxide, Dimethyl sulfide Morales, D. et al., Organometallics, 2001, 20(22), 4517... 

Di-tert,-butylphosphino)-biphenyl has been used by Buchwald [5] et al. as the most efficient ligand in the Pd-catalyzed amination of aryl chlorides. 2-Chloro-4-methyl-toluene can be aminated with pyrrolidine in 98% yield using sodium-tert.-butoxide [eq. (e)]. 

A domestic oven and open containers were used in the work by Sharifi, who performed couplings between aryl bromides and alkyl amines (yields 32-86%) [79]. The palladium precatalyst Pd[P(o -tolyfbhCk was found to be the most efficent catalyst when toluene was used as solvent and sodium tert-butoxide as base. About the same time, a similar approach to arylating alkyl and aryl amines was reported by Hallberg [80]. Mono-modal microwave... 

The base combination of sodium amide and sodium tert-butoxide in tetrahydrofuran (THF) containing a secondary amine converts halopyridines into aminopyridines via a pyridyne intermediate (Equation 82) <1997H(45)2113>. The regioselectivity varies depending upon the position and type of pyridine substituents. 

Palladium-catalyzed methods have also been applied to the synthesis of thiopyridines from halopyridines. 3-Chloropyridine undergoes cross-coupling with 1-hexanethiol to give the thiopyridine in 97% yield using 2.5 mol% of the the air-stable palladium(ll) complex 134 in the presence of sodium tert-butoxide in toluene under reflux <2001JOC8677> (Equation 97). 

The Buchwald-Hartwig reaction was performed under a variety of conditions starting with the model compounds and leading up to target substrate. The results are shown in Table 3. There was a 70 % yield obtained in the reaction of triflate 35 with the cyclic secondary amine morpholine using condition A (entry l),32 however the reaction fails with diphenethylamine (entry 2). Changing the base to sodium tert-butoxide (condition B) or the catalyst to Pd2(dba)3 and ligand (condition C) also resulted in no reaction (entries 3 and 4). 

The use of a strong base in the palladium-catalyzed amination of aryl halides precludes the use of many substrates, such as those with aromatic nitro groups or enolizable hydrogens, esters other than tert-butyl esters, and many substrates with base-sensitive stereochemistry such as some protected amino acids and heterocyclic substrates [191]. Thus, conditions that employ milder bases are required. A solution that involves reaction temperatures as low as those used for reactions conducted with sodium tert-butoxide has not been developed. However, carbonate and phosphate bases can be used with certain catalysts at reaction temperatures comparable to those of reactions involving the first- and second-generation catalysts. 

Representative Procedure for the Use of Benzophenone Imine as an Ammonia Equivalent (Excerpted with permission from [108]. 1996 Pergamon Press) A Schlenk tube was charged with sodium tert-butoxide (1.4 mmol), Pd2(dba)3 (0.00125 mmol), and BINAP (0.00375 mmol). The Schlenk tube was fitted with a septum and attached to a Schlenk line. After the air atmosphere was replaced with argon, toluene (4 ml), 4-tert-butylbromobenzene (1.0 mmol), and benzophenone imine (1.2 mmol) were added by syringe. After the septum was replaced with a teflon valve, the reaction was sealed and heated to 80 °C with stirring until starting material was consumed as judged by GC analysis. The reaction mixture was cooled to room temperature, diluted with ether (40 ml), filtered, and concentrated. The crude reaction mixture was then recrystallized from MeOH to furnish the desired product in 90% yield. 

Zim and Buchwald synthesized the palladacyclic phosphine complex 44 based on their ligand P(Bu-f)2(o-biphenyl) 13 (equation 46)157. This air- and moisture-stable palladium complex is a convenient one-component precatalyst for animation of aryl chlorides when combined with sodium tert-butoxide or sodium methoxide. For coupling of anilines, the addition of NEt3, which is possibly acting as the reducing agent to produce Pd(0), is necessary. 

Yu, R. H. Schultze, L. M. RohIoff,J. C. Dudzinski, P.W. Kelly, D. E., Process Optimization in the Synthesis of 9-[2-(Diethylphosphonomethoxy)ethyl]adenine Replacement of Sodium Hydride with Sodium tert-Butoxide as the Base for Oxygen Alkylation. Org. Process Res. Dev. 1999,3, 53. 

Sodium tert-butoxide tert-Butyl alcohol, sodium salt (8) 2-Propanol, 2-methyl-, sodium salt (9) (865-48-5)... 

Sodium tert-butoxide is purchased from Aldrich Chemical Company, Inc., and used without further purification. The bulk of this material is stored under nitrogen in a Vacuum Atmospheres Glovebox. Small portions (10-15 g) were removed from the glovebox in glass vials and weighed in the air. The checkers stored sodium tert-butoxide, purchased in 5-g bottles, in a desiccator and weighed it out in air. 

Sodium tert-butoxide was purchased from Aldrich Chemical Company, Inc. 

Chiral bases made by treatment of (i )-BINOC with a combination of lanthanum isopropoxide and sodium tert-butoxide have been used in asymmetrical Michael reactions to produce products with 92% ee.134... 

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