Alkyl iodides transfer catalyzed

Having determined the most appropriate extraction from plasma we investigated the simultaneous derivati-zation of A9-THC and ll-hydroxy-A9-THC. We have claimed that ethylation of 11-hydroxy-A9-THC proceeded by phase transfer catalysis (7). However, it is known that quaternary ammonium hydroxides are capable of catalyzing alkylations with alkyl iodides in aproptic solvents (8). Furthermore, we had not demonstrated that A9-THC could be derivatized under the same conditions as ll-hydroxy-A9-THC. We found that the minimum requirement for the reaction to proceed is the presence of water, which probably increases the degree of ionization of the quaternary ammonium hydroxide. However, in order for the reaction to go to completion, at least 0.1N NaOH is necessary. This supports the contention that this derivatization is, to some extent, a phase transfer catalyzed alkylation. 

It should be stressed that, on the other hand, the catalytic process proceeds efficiently with alkyl bromides whereas PT-catalyzed alkylation with alkyl iodides is inhibited by the iodide ions produced during the reaction. The interfacial alkylation of phenylacetonitrile with alkyl iodides is limited by the rate of transfer of iodide anions from the interface to the aqueous phase. 

They found that the reactions were actually catalyzed by quaternary ammonium salts generated in situ. In these reactions, sodium iodide was added as a cocatalyst and reacted with the alkyl chloride to yield an alkyl iodide which alkylated the tertiary amine. Once generated, the quaternary ammonium ion served as catalyst in the normal sense of a phase transfer catalyst, (see Eqs. 1.9—1.11). 

Although alkyl iodides do not undergo the usual palladium-catalyzed carbonylation reactions, they can be converted into carboxylic acid derivatives by radical atom transfer carbonylation. The reaction of primary alkyl iodides was shown to be accelerated by Pd(PPh3)4 catalyst, and this method was effectively used for the construction of the lactone ring of (—)-hinokinin [93]. 

RTCP involves a reversible chain transfer (RT) process with a catalyst (Scheme 4a) that improves the dispersity control, as well as the mentioned small contribution of DT (Scheme Id). The catalyst can be, e.g., Af-iodosuccinimide (NIS) (Scheme 4a) [31], and works as a deactivator. Polymer (which is originally supplied by the conventional radical initiator) reacts with NIS to produce N-succinimide radical (NS ). NS works as an activator of Polymer-I to generate Polymer and NIS again. This cycle allows for frequent reversible activation of Polymer-I. This process is a reversible chain transfer of NIS that catalytically activates Polymer-I. Therefore, the polymerization was termed reversible chain transfer catalyzed polymerization (RTCP). Regarding the components used, RTCP is similar to initiators for continuous activator regeneration (ICAR)-ATRP [65]. Both systems use a monomer, a dormant species (alkyl iodide or alkyl bromide), a conventional radical initiator, and a deactivator [NIS or copper (II)] to regenerate a highly reactive activator [NS or copper (I)]. 

Volatile alkyl halogenides such as methyl iodide, methylene chloride etc., react quantitatively with the solid methylamine salt of 5-benzylidene- (39a) [32] and 5,5-diphenylthiohydantoin (37) to form the anticonvulsive solids 225 and 226 in quantitative yield [28] (Scheme 30). Unlike the solution reaction, only the S-alkylation occurs under gas-solid conditions. Furthermore, various dialkylamidodithiolate salts 228 react readily with dichloromethane at 80 °C. The salts with the quaternary cations react at room temperature and it is also possible to catalyze the reaction of the sodium salt by admixture of 10% of the corresponding phase transfer bromides [28]. These reactions have been tuned for removal of dichloromethane from loaded air streams [28]. 

The use of thiazolium salts enables the benzoin condensation to proceed at room temperature. It can also be performed in dipolar aptotic solvents or under phase transfer conditions. Thiazolium salts such as vitamin Bi, thiazolium salts attached to y-cyclodextrin, macrobicyclic thiazolium salts, thiazolium carboxylate, ° naphtho[2,l-d]thiazolium and benzothiazolium salts catalyze the benzoin condensation and quaternary salts of 1-methylbenzimidazole and 4-(4-chlorophenyl)-4//-1,2,4-triazole are reported to have similar catalytic activity. Alkylation of 2-hydroxyethyl-4-methyl-l,3-thiazole with benzyl chloride, methyl iodide, ethyl bromide and 2-ethoxyethyl bromide yields useful salts for catalyzing 1,4-addition of aldehydes to activated double bonds. Insoluble polymer-supported thiazolium salts are catalysts for the benzoin condensation and for Michael addition of aldehydes. Electron rich al-kenes such as bis(l,3-dialkylimidazolidin-2-ylidenes) bearing primary alkyl substituents at the nitrogen atoms or bis(thiazolin-2-ylidene) bearing benzyl groups at the nitrogen atoms are examples of a new class of catalyst for the conversion of ArCHO into ArCHOHCOAr. 

Additionally, if the initiation reaction is more rapid an the chain propagation, a very narrow molecular weight distribution, MJM = 1 (Poisson distribution), is obtained. Typically living character is shown by the anionic polymerization of butadiene and isoprene with the lithium alkyls [77, 78], but it has been found also in butadiene polymerization with allylneodymium compounds [49] and Ziegler-Natta catalysts containing titanium iodide [77]. On the other hand, the chain growth can be terminated by a chain transfer reaction with the monomer via /0-hydride elimination, as has already been mentioned above for the allylcobalt complex-catalyzed 1,2-polymerization of butadiene. 

Allyl amines in the form of their ammonium salts can be used as substrates for palladium(O)-catalyzed alkylations. They are particularly interesting because they are easily obtained optically pure from amino acids. (S)-l-Isobutenyl-2-(Z)-butenyl trimethyl ammonium iodide yields with high regioselectivity the (5)-( )-alkene 55. The C-N chirality is almost completely transferred to the newly formed C —C bond. The double-bond geometry and the configuration of the stereocenter is simultaneously inverted, thus the reaction proceeds under net retention of configuration via a syn-syn-n allylpalladium complex, which is formed by n-a-n rearrangement123. 

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