Triethylamine Triphenylphosphine

A cousin to this reduction is one using stannous chloride (a.k.a. SnCb, a.k.a. Tin chloride) which is done exactly as the calcium one except that about lOOg of SnCb is used in place of the Mg or Ca and the addition occurs at room temperature and the solution is stirred for one hour rather than 15 minutes. Some very good reductions that operate almost exclusively at room temperature with no pressure and give almost 100% yields are to follow. The only reason Strike did not detail these methods is that some of the chemicals involved are a little less common than Strike is used to but all are available to the public. These alternatives include acetlylacetone and triethylamine [73], propanedithlol and trieth-ylamine [74], triphenylphosphine [75], NaBH4 with phase transfer catalyst [76], H2S and pyridine [77], and palladium hydrox-ide/carbon with hydrazine [78], stannous chloride dihydrate [85]. 

Benzyl chloride undergoes self-condensation relatively easily at high temperatures or in the presence of trace metallic impurities. The risk of decomposition during distillation is reduced by the use of various additives including lactams (43) and amines (44,45). Lime, sodium carbonate, and triethylamine are used as stabilizers during storage and shipment. Other soluble organic compounds that are reported to function as stabilizers in low concentration include DMF (46), arylamines (47), and triphenylphosphine (48). 

During the course of an elegant synthesis of the multifunctional FR-900482 molecule [( )-43, Scheme 9], the Danishefsky group accomplished the assembly of tetracycle 42 using an intramolecular Heck arylation as a key step.24 In the crucial C-C bond forming reaction, exposure of aryl iodide 41 to a catalytic amount of tetra-kis(triphenylphosphine)palladium(o) and triethylamine in acetonitrile at 80 °C effects the desired Heck arylation, affording 42 in an excellent yield of 93 %. The impressive success of this cyclization reaction is noteworthy in view of the potentially sensitive functionality contained within 41. 

In 1988, Linstrumelle and Huynh used an all-palladium route to construct PAM 4 [21]. Reaction of 1,2-dibromobenzene with 2-methyl-3-butyn-2-ol in triethylamine at 60 °C afforded the monosubstituted product in 63 % yield along with 3% of the disubstituted material (Scheme 6). Alcohol 15 was then treated with aqueous sodium hydroxide and tetrakis(triphenylphosphine)palladium-copper(I) iodide catalysts under phase-transfer conditions, generating the terminal phenylacetylene in situ, which cyclotrimerized in 36% yield. Although there was no mention of the formation of higher cyclooligomers, it is likely that this reaction did produce these larger species, as is typically seen in Stephens-Castro coupling reactions [22]. 

Disubstituted-amino)triphenylphosphonium bromides (72) have been obtained from the reaction of triphenylphosphine dibromide and secondary amines in the presence of triethylamine. ... 

The l-acyl-3-methylimidazole-2-thiones are easily obtained either from bis-l-methyl-2-imidazole disulfide, a carboxylic acid, and triphenylphosphine, or from 2-mercapto-l-methylimidazole and a carboxylic acid chloride in the presence of triethylamine.[32 ... 

Dehydration of (3-nitro alcohols using DCC gives a mixture of E/Z nitroalkenes 48 The pure (E)-isomers are obtained on treatment with catalytic amounts of triethylamine or polymer-bound triphenylphosphine (TPP) (Eq. 3.28).51 When (Z) nitroalkenes are desired, the addition of PhSeNa to the E/Z mixture and protonation at -78 °C followed by oxidation with H202 gives (Z)-nitroalkenes (Eq. 3.29).52... 

When electron-deficient alkenes are very reactive, weak bases such as triethylamine or triphenylphosphine (Eq. 4.105)134 are reactive enough as base. On the other hand, stronger bases... 

Ozonolysis of alkene 446 in the presence of acetaldehyde afforded diketone 448 through the intermediacy of 447. Ring expansion through Beckmann rearrangement took place when bis-oxime 449 was mesylated and warmed in aqueous tetrahydrofuran (THF). The bis-lactam so formed gave piperidinediol 450 on reduction with lithium aluminium hydride, and this compound was transformed into ( )-sparteine by treatment with triphenylphosphine, CCI4, and triethylamine (Scheme 105) <20050BC1557>. 

A convergent synthesis of chiral 6,5-bicyclic hexahydropyridazine derivative 394 is described. Methyl ester 391 is deprotected with perchloric acid in aqueous THF to provide the corresponding diol 392. Its cyclization is achieved by refluxing its dichloromethane solution with excess triphenylphosphine, tetrachloromethane, and triethylamine. The crude hydroxy derivative 394 is separated from triphenylphosphineoxide via the corresponding silylated derivative 393 (Scheme 60) <1995H(41)2487>. 

Bromobenzene (0.63 g, 4.0 mmol) was added to a stirred mixture of diethyl phosphite (0.61 g, 4.4. mmol), triethylamine (0.44 g, 4.4 mmol), and tetrakis(triphenylphosphine)palladium (0.23 g, 0.2 mmol) under a nitrogen atmosphere. The mixture was stirred for... 

The /V -hydroxylamino compounds (404) and (405), obtained from the reaction of tert-butyl acetate with 3,4-dihydroisoquinoline-A-oxide or 5,5-dimethyl-pyrroline-/V-oxide, when boiled in methylene chloride in the presence of triphenylphosphine, carbon tetrachloride and triethylamine, are transformed to (1,2,3,4- tetrahydroisoquinolin-l-ilidene) acetate (406) or (pyrrolidin-2-ilidene) acetate (407) (Scheme 2.181) (645). 

Davies et al. describe the preparation of both oxazole- and thiazole-containing derivatives of combretastatin. By formation of the ketoamide intermediate 60, in a 54% yield (Scheme 14), both classes of compounds may be obtained by altering the last step of the reaction [58]. To produce the oxazole 61 a cyclo-dehydration reaction was performed using triphenylphosphine-iodine-triethylamine, and the thiazole compound 62 was formed by thiona-tion using Lawesson s reagent, with an excellent yield (94%). 

An efficient pathway to 3,8-dihydro derivatives of the same ring system 496 was published by Lee et al. < 1994S1057, 1997S1461 > the ureido ethylidenehydrazones of type 494 were treated with triphenylphosphine in the presence of triethylamine in a carbon tetrachloride solution under refluxing conditions to yield the product 496 in acceptable yields. The transformation was rationalized to proceed via the zwitterionic intermediate 495. It is important to note that, in the cases of R = aryl group, the reaction proceeded in a totally different direction to furnish... 

When reacted with trialkyl phosphite in benzene for 1 hr, dialkyl magnates (364, X = F) gave a mixture of amino(trifluoromethyl)methylene-malonates (365) (20% yields), dialkyl trifluoromethyl(substituted amino)-methylenemalonates (366) (40-45% yields), and dialkyl chlorophosphate (-20%) (86ZOB805). The reactions of dialkyl malonates (364, X = F, Cl) and triphenylphosphine in the presence of triethylamine in diethyl ether for 1 hr gave trihalomethyl(substituted amino)methylenemalonates (367) in 87-95% yields. The treatment of a solution of dialkyl trifluoromethyl-(substituted amino)methylenemalonates (366, R1 = Et) in benzene with aqueous hydrochloric acid gave amino(trifluoromethyl)methylene-malonates (368) in 82-84% yields (86ZOB805) (Scheme 32). 

The action of triphenylphosphine dichloride, generated from triphenylphosphine and hexachloroethane, on tertiary amines leads to phosphonium salts. Triethylamine is converted into 351 and ethyldiisopropylamine gives a mixture of the salts 352 and 353391. 

Ketenimines (144), generated from a-substituted benzophenone 1-acetamidoethyl-idenehydrazones with a mixture of triphenylphosphine, carbon tetrachloride and triethylamine in dichloromethane (Appel s conditions), have been used to synthesize a variety of 1,2,4-triazole-fiised heterocycles (see Scheme 56). Mechanistically, the... 

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