Phase-Transfer Conditions PTC

Af-Methylation of the thienodiazepinedione 1 is achieved by treatment with dimethyl sulfate under phase-transfer conditions (PTC).307... 

In a similar process, nickel compounds also catalyze the carbonylation of allenyl halides, under phase-transfer conditions (PTC), to give allenyl acids in poor to reasonably good yields (equation 94)368. 

Intramolecular N-alkylation under phase-transfer conditions (PTCs) of 236 and 237 having the triisopropylbenze-nesulfonyl (TIBS) protecting groups give the corresponding clavams 238 where R = a-H and /3-H, respectively... 

Procedure A is very effective for most monosubstituted and 1,2-di-substituted olefins. This method,2 using phase-transfer conditions (PTC), has been developed recently in our laboratory and represents a substantial improvement over our former procedures.4 Cyclooctene, (Z)-5-decene, stilbene, ethyl crotonate, and 1-decene are among the olefins that are readily oxyaminated under the conditions described in procedure A. 

The thrust of our research has been to incorporate the BPC moiety into a polymer backbone that can impart flame retardancy without additives. The incorporation of this monomer into a thermoplastic has been approached in several ways including the following nucleophilic aromatic polymerizations, nucleophilic displacement under phase transfer conditions (PTC), " diene metathesis,and vinyl addition polymerization. ... 

Recently, asymmetric reactions catalyzed by metal-free compounds (organoca-talysis) have received increased attention due to the potential advantages of these types of systems [4]. This is primarily due to the operational simpUcity and the obvious industrial applications. This chapter covers recent developments, from 2007 to date, in the area of the enantioselective organocatalytic Henry reaction with an emphasis on catalytic methods based on Bronsted bases, Bronsted acids, and phase-transfer conditions (PTC) approaches. 

In 2006, Ooi conducted an asymmetric Strecker reaction under phase-transfer conditions (PTC) employing a chiral quaternary ammonium salt 76 with a tetrana-phthyl backbone (Scheme 30.18) [43]. Under biphasic conditions, aqueous KCN could be used as an inexpensive and safe surrogate for HCN. With lmol% of catalyst 76 the reaction in toluene-water at 0°C proceeded smoothly in relatively short reaction times (2-8h). In doing so, a-branched and a-unbranched aUphatic N-mesitylenesulfonyl imines 75 were transformed in high yields and good to high... 

The nitriles obtained by reaction of HPhCN ion with heteroaryl halides can lead to the corresponding ketones in excellent yields (77%) by oxidative decyanation under phase-transfer conditions (PTCs) ... 

Although the use of phase-transfer catalysis (PTC) for manufacturing esters has the merits of a mild reaction condition and a relatively low cost [1], PTC has its limitations, such as the low reactivity of carboxylic ion by liquid-liquid PTC [2], a slow reaction rate by solid-liquid PTC, and the difflculty of reusing the catalyst by both techniques. 

The synthetic procedure used for the chemical modification of PPO involved in the first step the radical bromination of PPO methyl groups to provide a polymer containing bromobenzyl groups. The bromobenzyl groups were then esterified under phase-transfer-catalyzed (PTC) reaction conditions with potassium 4-(4-oxybiphenyl)butyrate (Ph3C00K, Ph3C00-PP0), potassium... 

Compounds 242 when treated with trimethylsulfonium iodide under phase-transfer catalysis (PTC) conditions ( -Bu4XI, dichloromethane, 50% NaOH) provide mixtures of the corresponding 2-oxiranylvinyl benzotriazoles 243 and 18-83% yields of heteropentalenes 244. The ratio of these two main products is highly dependent on the R substituent (Scheme 29) <2004ARK(ii)109>. 

Alkylation of dianhydrohexitols under phase-transfer catalysis (PTC) conditions... 

Loupy and Soufiaoui described a comparative study of the reactivity of diphenylnitri-limine 200 with several dipolarophiles under microwave irradiation in the absence of solvent using a solid mineral support or phase-transfer catalysis (PTC) conditions (Scheme 9.62) [30b]. The results showed that the best yields of adducts were achieved upon impregnating KF-alumina with a mixture of the hydrazynoyl chloride 199 and the dipolarophile followed by irradiation of the mixture in a focused oven. Reaction of this mixture under solid-liquid PTC conditions with KF-Aliquat under microwaves afforded lower yields of cycloadducts, perhaps owing to the partial decomposition of Aliquat at the reaction temperature (140 °C). In all cases, worse yields were obtained by classical heating under comparable reaction conditions (time and temperature). 

We have exploited this base catalysis of the oxygen exchange process to effect oxygen lability in the less electrophilic carbonyl sites of neutral metal carbonyl species. Because [MCOOH] intermediates are readily decarboxylated in the presence of excess hydroxide ion, in order to observe oxygen exchange processes in neutral metal carbonyl complexes it was convenient to carry out these reactions in a biphasic system employing phase transfer catalysis () (16, 17. 18). Under conditions (eq. 7) the... 

In some reactions, the choice of PTC can actually alter the distribution of products for example, the reaction of t-butyl acrylate with chloroform under basic phase transfer conditions gives two major products, as illustrated in Scheme 5.8, the amounts of which are catalyst dependent [46],... 

One of the early examples for organocatalysis is the asymmetric Weitz-Scheffer epoxidation of electron-deficient olefins, which can be effected either by organic chiral phase transfer catalysts (PTC) under biphasic conditions or by polyamino acids. This reaction has gained considerable attention and is of great synthetic use. 

The development of new procedures in this area in the last decade seems scarce. 3, 3-Disubstituted alkenylidenes are generated from 2,2-disubstituted 1,1-dibromocyclo-propanes under phase-transfer-catalysis (PTC) conditions and added to a variety of electron-rich alkenes to give vinylidenecyclopropanes in good yields (equation 85)143. 

Pc Pen Pip Ph ppm Pr PTC Pyr phthalocyanine pentyl (C5Hu) piperidyl (C5H10N) phenyl parts per million propyl (also /-Pr or Pr ) phase transfer catalysis or phase transfer conditions pyridyl (C5H4N)... 

Undoubtedly the most important and widely used procedure for the generation of dichlorocarbene involves the reaction of chloroform with aqueous sodium hydroxide under the conditions of phase transfer catalysis (PTC), introduced by Makosza.20-22 Under these conditions chloroform reacts with sodium hydroxide to form sodium trichloromethylide which on exchange with a quaternary ammonium salt, usually benzyltriethylammonium chloride, is converted to the unstable quaternary ammonium methylide which dissociates in the organic phase to give dichlorocarbene. The dichlorocarbene irreversibly adds to the alkene (Scheme 1). 

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