3- Butyn-l-ols

As an application of maleate formation, the carbonylation of silylated 3-butyn-l-ol affords the 7-butyrolactone 539[482], Oxidative carbonylation is possible via mercuration of alkynes and subsequent Lransmetallation with Pd(II) under a CO atmosphere. For example, chloromercuration of propargyl alcohol and treatment with PdCF (1 equiv.) under 1 atm of CO in THF produced the /3-chlorobutenolide 540 in 96% yield[483]. Dimethyl phenylinale-ate is obtained by the reaction of phenylacetylene, CO, PdCU, and HgCl2 in MeOH[484,485]. 

The alkynylation of estrone methyl ether with the lithium, sodium and potassium derivatives of propargyl alcohol, 3-butyn-l-ol, and propargyl aldehyde diethyl acetal in pyridine and dioxane has been studied by Miller. Every combination of alkali metal and alkyne tried, but one, gives the 17a-alkylated products (65a), (65c) and (65d). The exception is alkynylation with the potassium derivative of propargyl aldehyde diethyl acetal in pyridine at room temperature, which produces a mixture of epimeric 17-(3, 3 -diethoxy-T-propynyl) derivatives. The rate of alkynylation of estrone methyl ether depends on the structure of the alkyne and proceeds in the order propar-gylaldehyde diethyl acetal > 3-butyn-l-ol > propargyl alcohol. The reactivity of the alkali metal salts is in the order potassium > sodium > lithium. 

QHijOjP 122-52-1) see Foscamet sodium Gesirinone 7-O-triethylsilylbaccatin III (C,7H520 Si 115437-21-3) see Paclitaxel 4-triethylsilyl 3-butyn-l-ol triethylsilyl ether (C 4Hj40Si2 160194-28-5) see Rizatriptan benzoate triethylsilyl chloride... 

The key Pd-catalyzed coupling step to the indole was optimized by judicious choice of the protection group on 3-butyn-l-ol, screening of different reaction parameters such as bases and additives, and implementing a fine-tuned, yet practical work-up procedure. Tryptophol 27 was isolated in 76-82% yield by crystallization. 

The dinuclear isonitrile and alkoxycarbene complexes 6 and 7 were obtained from [Fe(CO)3( X-dppm) Tl2- j,2-Si(OMe)2(OMe))PtCl] by chloride substitution with isonitriles and 3-butyne-l-ol (or ( )-4-pentyne-2-ol), respectively [2], In these complexes, the organic ligand bound to Pt only occupies one coordination site, thus allowing the trimethoxysilyl ligand to display a T 2- i2-Si-0 bonding mode. 

In one experiment the checkers used 3-butyn-l-ol available from Aldrich Chemical Company, Inc., and found that it was of satisfactory purity. In other experiments, both the submitters and the checkers prepared the hydroxy compound from sodium acetylide and ethylene oxide in liquid ammonia according to the procedure described by Schulte and Reiss3 and further attempted to maximize the yield by varying the ratio of sodium ethylene oxide liquid ammonia used ip the reaction. Unfortunately, the checkers failed to obtain consistent results in repeated experiments and consequently could not define the optimum conditions for the reaction. Thus, the yield of 3-butyn-l-ol varied from 15 to 45% and 15 to 31% on the basis of sodium and ethylene oxide, respectively. Unknown and apparently subtle experimental factors affect the yield significantly. 

When 3-butyn-l-ol was added to a solution of the anhydride cooled to 0° and then the mixture was allowed to react at room temperature for 3 hours, the yield of the sulfonate dropped to 70-75%. 

Low-temperature reduction of 4-aryl-substituted 3-butyn-l-ols with lithium aluminum hydride in THF solvent gave m-olefin resulting from the hydride addition at the -carbon of the triple bond.134 This was in contrast to the propargyl alchohol that gives the trans-product resulting from the 7-addition. 

Benzophenone does not react under these conditions. However, when a prior transmetallation between 30 and phenyllithium is performed, and the new organolithium compound is allowed to react with benzophenone, the homopropagylic alcohol l,l-diphenyl-3-butyn-l-ol 32 is obtained in 69% yield (Equation (16)).49... 

The formation of cyclic Fischer carbene complexes by ruthenium-mediated activation of 3-butyn-l-ol and 4-pent5m-l-ol has been reported before (147,155,158-164). Correspondingly, a reaction of [Ru(bdmpza)Cl(PPh3)2] (24) with these terminal alkynols results... 

With telluronium salt (d) (typical procedure) A solntxon of n-BuLi (1.5 mmol) in hexane is added to a solution of the telluronium salt (0.65 g, 1.5 mmol) in dry THF (10 mL) at -78°C under N2. After 30 min, a solution of p-chlorobenzaldehyde (0.168 g, 1.2 mmol) in THF (2 mL) is added dropwise at -78°C and the reaction mixture is allowed to warm at room temperature. After the reaction is complete (monitored by TLC), H2O (1 mL) is added and the solution is stirred for another 1 h. The mixture is then extracted with ether (3x5 mL). The combined extracts are washed with brine, dried (Na2S04), filtered and concentrated under vacuum. Flash chromatography on an SiOj column gives l-(p-chlorophenyl)-4-(trimethylsilyl)-3-butyn-l-ol (0.265 g (87%) (98% GC purity)). 

The reagents, 3-butyn-l-ol and 2.0 M ethylmagnesium bromide in tetrahydrofuran, were purchased from Aldrich Chemical Company, Inc. The... 

The combined organic phases are washed with two 200-mL portions of water, four 200-mL portions of saturated sodium bicarbonate solution, and two 200-mL portions of saturated sodium chloride. The organic phase is dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure at room temperature using a rotary evaporator. The crude product is distilled through a short-path distillation apparatus under reduced pressure to give 45.2 g (0.318 mol, 71% yield) of 4-(trimethyls11yl)-3-butyn-l-ol, bp 78-79°C (10 mm), as a colorless liquid (Notes 4 and 5). 

In a formal total synthesis of matrine (116), Yamanaka and coworkers used the Sonogashira reaction of pyridyl halides as the means to form C—C bonds <86CPB2018>. For instance, bromonaphthyridinone 114 was coupled with 3-butyn-l-ol to furnish alkynylnaphthyridinone 115, an intermediate towards matrine (116). 

Silylformylation of 3-butyn-l-ol 84 results in concomitant formation of 7-lactone 86 (Scheme 3). The lactone formation becomes exclusively preferred by use of 1 equiv. of EtsN (Equation (34))." ... 

A. 3-Butyn-l-yl Trifluoromethanesulfonate. A 500-ml., three-necked flask is fitted with a mechanical stirrer, a pressure-equalizing dropping funnel, and a stopper. The system is flushed with nitrogen through a gas-inlet tube attached to the top of the funnel. To 150 ml. of dry methylene chloride (Note 1) in the flask is added 75 g. (0.27 mole) of trifluoromethanesulfonic acid anhydride (Note 2), and the solution is cooled to —40°. After addition of 14.5 g. (0.14mole) of finely powdered anhydrous sodium carbonate (Note 3), 15 g. (0.21 mole) of 3-butyn-l-ol (Note 4) is added dropwise over a 20-minute period to the well-stirred reaction mixture maintained at —40° to —55°. Stirring is continued at —30° for 2 hours and then at 0° for another hour, and finally the... 

This is further indicated in the reactions of 3-butyn-l-ol with [Fe( /2-CH2=CMe2)(CO)2( -C5H5)]+, which afford a mixture of dihydrofuran complex (64) and the oxacyclopentylidene complex (65) (84). The formation of these two derivatives involves a common tp-alkyne intermediate, which either forms 64 directly by internal nucleophilic attack of the oxygen on the complexed C=C triple bond, or rearranges to the vinylidene. This forms 65 by a similar attack of the hydroxy group on the a-carbon, followed... 

The hydrosilylation of 3-butyn-l-ol, i.e. homopropargyl alcohol, with HSiMe2Ph catalyzed by (Cy3P)Pt(CH2=CH2)2 gives a 4.2 1 mixture of (E)-4-silyl- and (E)-3-silyl-3-buten-l-ols135, whereas the cationic rhodium complex-catalyzed reaction with HSiEt3 affords ( )-4-triethylsilyl-3-buten-l-ol (136) exclusively in 97% yield (equation 55)136. 

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