N-Butyllithium in pentane

The submitter used a 1.24M solution of n-butyllithium in pentane obtained from Foot Mineral Co., and the checkers used a 1.45M solution of w-butyllithium in hexane obtained from Wako Pure Chemical Industries Ltd. (Japan). The nominal titer of active alkyl on the bottle agreed well with the value found by titration2 with 0.S0M (submitter) or 0.50JJ (checkers) solution of 2-butanol in xylene using 1,10-phenan-throline as indicator. 

The ate complex is prepared by reaction of B-n-butyl-9-borabicyclo[3.3.1]nonane (9,76 77) with n-butyllithium in pentane or hexane. 

However, when w-butyllithium was used, twice as much 7 as 8 was observed. With sec-butyllithium a similar ratio of products was noted, but the overall yield of rearranged amines was lower. It was noted 95> that the anion may influence this reaction just as it does in the reaction of tetraalkylammonium salts. For example, the iodide of 6 was much less reactive than the chloride when treated with n-butyllithium in pentane, but differences in solubility may account for these observations. 

N butyllithium in pentane added dropwise with vigorous stirring at -70° during ca. 15 min. to a soln. of diethyl isocyanomethylphosphonate in tetrahydrofuran, the resulting suspension treated at -60° with a soln. of cyclohexanone in tetrahydrofuran, and allowed to warm to room temp. cyclohexylidenemethyliso-cyanide. Y 84%. F. e., also from aldehydes, s. U. Sdiollkopf, R. Schroder, and D. Stafforst, A. 1974, 44. 

A 1.4 M soln. of n-butyllithium in pentane added at -78 to -70° during 15 min. with vigorous stirring to a suspension of bis (diethylcarbamyl) mercury in anhydrous tetrahydrofuran, the resulting soln. added at - 70° to a soln. of aceto-... 

To a three-necked 100-mL flask equipped with mechanical stirrer, jacketed dropping funnel and rubber septum, under argon, are added 3.52 g (15 mmol) of (-)-sparteine, 20 mL of anhvd pentane, 3 mL of cyclohexane and 2.99 g (15 mmol) of ( )-2-bulenyl diisopropylcarbamate. The mixture is chilled to below -70 C in a dry ice/acetone bath. 10 mL of 1.6 N butyllithium in hexane are slowly added with rapid... 

To a suspension of 2.24 g (20 mmol) of potassium rerf-butoxide in 20 mL of terf-butyl methyl ether under argon is added 2.31 g (10 mmol) of (S)-2-(methoxymethyl)-1-[( )-3-phenyl-2-propenyl]pyrrolidine30, and then the mixture is cooled lo — 78 °C and 7.1 mL of 1.69 M fm-butyllithium in pentane is added dropwise with stirring. After 2 h, 12 mmol of the haloalkane are added and the mixture is stirred until the brown-red solution becomes yellow. Then 30 mL of diethyl ether and 20 mL of 2 N hydrochloric acid are added, the mixture stirred for 12 h at 25 °C, extracted with three 40-mL portions of CH2CI2, the organic layer is washed with two 10-mL portions of NaHCOj and two 10-mL portions of water, dried with Na2S04, concentrated in vacuo and distilled (Kugelrohr). 

A 2-L, three-necked flask was equipped with an overhead mechanical stirrer, a Claisen adapter which contained a low-temperature thermometer, and a no-air stopper which held a gas dispersion tube for the introduction of carbon monoxide (Note 1). The flask was charged with 400 mL each of tetrahydrofuran (THF) and diethyl ether, 100 mL of pentane, and pinacolone (7.92 g, 79.1 mmol) (Note 2). The reaction solution was cooled to -110 C (Notes 3 and 4) under an argon atmosphere and carbon monoxide (Note 5) was bubbled in for 30 min. Then a solution of butyllithium (2.53 N solution in pentane, 31.0 mL, 78.43 mmol) (Note 6) was added at 0.6-1.0 mL/min by means of a syringe pump (Note 7). The reaction mixture was orange after the addition had been completed. The reaction mixture was stirred at -110°C for 2 hr while the carbon monoxide stream was continued. The liquid nitrogen Dewar was removed, and the reaction mixture was allowed to warm to room temperature over the course of 1.5 hr, during which time the color changed to yellow. 

Butyllithium in pentane was purchased from Alfa Products, Morton/Thiokol Inc. and was titrated by the method of Gilman and Cartledge.23 The checkers used a 1.56 N hexane solution purchased from Mitsuwa Chemical Co. after titration by th Kofron-Baclawski procedure.215... 

To a solution of 25.27 g (102.3 mmol) of [ClPNCHMe2]2 in 50 mL of diethyl ether a solution of 102.3 mmol of (Me3Si)(Me2CH)NLi [prepared from 13.42 g (18.9 mL, 102.3 mmol) of (Me3SiXMe2CH)NH in 50 mL of diethyl ether and 102.3 mmol of n-butyllithium in hexane] is added dropwise (30 min) with magnetic stirring at -16° (ice-sodium chloride mixture). [Note The stoichiometry must be exact even a small excess of LiN(i-Pr)TMS induces decomposition.] After removal of the cold bath the reaction mixture is stirred for 45 min at room temperature and reduced in volume to approximately 50 mL. Lithium chloride is filtered off (D4 frit) and washed twice with 10 mL of pentane. The solvent is removed under reduced pressure (0.01 torr) to yield 33.1 g (95%) of an orange-brown oil (crude). 

M solution of n-butyllithium in n-hexane were carefully added via a syringe. After stirring 30 min at 0°C the solution was cooled to -78 °C and a solution of 11.9g (50 mmol) of ethyl-l-(4-methyl-3-pentenyl)-2-oxocyclopentane-l-carboxylate 4.15a in 10 mL of dry THF was added dropwise over a period of 10 min. After 1 h at -78 °C 11 mL (87 mmol) of chlorotrimethylsilane were added, the solution was allowed to warm up, and stirred at room temperature for 1 h. The solvent was evaporated, the residue was suspended in 50 mL of dry pentane, and LiCl was removed by filtration. After evaporation of toe solvent the crude product was distilled (96 °C/0.05 mbar) to give 12.8 g (83%) of etoyl-l-(4-methyl-3-pentenyl)-2-trimethylsilyloxy-cyclopent-2-enyl-l-caiboxylate as a colorless oil. 

The relative product ratios of the regioisomers 6 and rac-5 varied according to the reaction conditions. The highest (relative) amount of compound 6(11 1 product ratio) was found using the polar solvent THF, and the product ratio most in favor of rac-5 (2.4 1) was found in the non-polar solvent n-pentane. We made a similar observation during the lithiation of benzyldimethyl-(piperidinomethyl)silane [Ig]. When benzyldimethyl(piperidinomethyl)silane was treated with 1 equiv of /crt-butyllithium in -pentane or toluene at -90 °C, one of the methyl groups was lithiated selectively. Selective metalation of the benzyl position under formation of 1 occurs only when the same reaction is carried out in a polar donor solvent, such as THF. 

To 40 mL THE at -78°C under nitrogen was added 11 mmol r-butyllithium in pentane, followed by 1.76 g 2-chloromethyl-4,4,6-trimethyl-5,6-dihydro-l,3-oxazine (10 mmol) in 10 mL THE. The mixture was stirred for 30 min, and 10 mmol benzyl bromide was added via syringe. The mixture was allowed to stir for 2 h, and quenched at -30°C with cold 1 N HCl, then washed with pentane. The pentane extracts were discarded. The aqueous acid solution was neutralized with NaHCOs, extracted with ether, and concentrated. Vacuum distillation of the residue at 0.15 mmHg afforded 72% of 2-(l-chloro-2-phenylethyl)-4,4,6-trimethyl-5,6-dihydro-l,3-oxazine, b.p. 98°C (0.15 mmHg), which solidified from pentane. 

A ca. 2.5 N soln. of butyllithium in pentane added dropwise below -70° with vigorous stirring to a soln. of ethyl isocyanoacetate in tetrahydrofuran, then a soln. of benzaldehyde in tetrahydrofuran added at -60°, and allowed to warm to room temp. -> ethyl a-formylaminocinnamate. Y 74%. F. e. s. U. Sdiollkopf, G. Gerhart, and R. Sdiroder, Ang. Ch. 8J, 701 (1969). 

The B-(Z)-l-alkenyl-9-BBN, however, are prepared from (Z)-l-lithio-l-al-kene [17] and B-OMe-9-BBN. (Z)-l-lodo-l-alkene [18] on reaction with t-butyllithium in pentane affords the corresponding (Z)-l-lithio-l-alkene. The treatment of a solution of (Z)-l-lithio-l-alkene in diethylether-n-pentane mixture at -78 °C with B-OMe-9-BBN in THF affords the ate complex. Treatment of the ate complex with 1.33 equiv of borontriffuoride-diethyl etherate at -78 °C, followed by warming results in the formation of the desired B-(Z)-l-alkenyl-9-BBN (Chart 23.10 Table 23.7) [19]. 

C yielded (3), which was isolated by evaporation of solvent and extraction with pentane. The next step was done under nitrogen and with extreme care to exclude air and moisture one equivalent of n-butyllithium in hexane was added slowly at... 

Optically active compds. A soln. of er butyllithium in pentane added at -78 under Ng to an ethereal soln. of n-butyl p-tolyl sulfoxide, and the product isolated after 0.5 hr. at -78° n-butyl er butyl sulfoxide. Y 76%. F. e. and procedures s. J. P. Lockard, C. W. Sdiroeck, and C. R. Johnson, Synthesis 1973, 485. 

A soln. of /err-butyllithium in pentane added dropwise at -30° during ca. 0.5 hr. to a mixture of ethyl vinyl ether and N,N,N, N -tetramethylethylenediamine in pentane, stirring continued ca. 40 min. at -30°, benzaldehyde added, stirred 10 min. at the same temp., methanol added with vigorous stirring followed by acidification with aq. HCl phenylacetylcarbinol. Y 57%. U. Schbllkopf and P. Hanssle, A. 763, 208 (1972). 

Preparation by treatment of m-bromophenol in tetra-hydrofuran with tert-butyllithium in pentane for 15 min at -78° under argon, after which a solution of cyclohexyl-N,0-dimethylhydroxamide in tetrahydrofuran was slowly added (60%). -Refer to Chem. Abstr., 119, 49010t (1993). m.p. 70-72° Spectra (NA). 

A mixture of 2.0 mmol of a 1.6 N solution of butyllithium in hexane and 0.47 g (2.0 mmol) of(-)-spartcinc in 10 mL of diethyl ether is stirred for 15 min at — 78 rC then 0.26 g (2.0 mmol) of 1-methyl-l//-indene in 2 mL of diethyl ether are added. Stirring is continued for 30 inin at 20 °C, the mixture is cooled to — 70 CC and 2.5 mmol of the acid chloride in 2 mL of diethyl ether are added. After stirring for 4h the usual aqueous workup was accomplished by addition of 10 mL of diethyl ether and successive washing with 10 mL of 2 N aq HC1. water and sat. aq NtiCl, respectively, followed by chromatographic purification on silica gel with diethyl cthcr/pentane. 

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