Alkyl halogenides

Deuterolyse primarer Alkyl-halogenide wurde bewiesen, daB vor der Reduktion eine Um-lagerung zum stabileren Carbokation eintritt1. 

Exhaustive studies on well-defined systems are rather scarce (4) nevertheless 3 systems thoroughly analyzed by independant research groups are of outstanding interest a) the quaternization of polyvinylpyridines by alkyl halogenides (20-25) b) the chlorination of polyethylene (13,26-28) c) the basic or acid hydrolysis of PMMA (29-31). On the other hand, neighbouring groups effects have been quantitatively taken into account for the kinetic analysis of periodate oxidation of amylose (32,33). 

Interactions of CO2 with alkyl halogenides include dissociative electron transfer and... 

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]. 

Alkyl-halogenide konnen auch durch Reaktion mit Diphenylsulfilimin und reduktive Spaltung der N-Alkyl-sulfilimine in primare Amine (z. B. Benzylamin) umgewandelt werden1. 

Alkyl-halogenide reagieren mit l,3,5-Trialkyl-hexahydro-l,3,5-triazinen in Methanol in Gegenwart von etwas Wasser zu Dialkyl-methyl-aminen4 ... 

R R2,R3 — Alkyl R4—X — Alkyl-halogenid. Benzoylchlorid und andere Elektrophile R5= Alkyl, CfiH,... 

Wenn man ahnlich wie oben beschrieben verfahrt, jedoch anstelle von Trifluormethan-sulfonsaure-trimethylsilylester/Casiumfluorid ein reaktives Alkyl-halogenid (1-Jod-butan, Benzyl-bromid, Bromessigsaure-ethylester) verwendet, erhaltman substituierte 1-Alkyl-pyrrolidine1, z.B. l-Butyl-3,4-dimethoxycarbonyl-2-phenyl-pyrrolidin (82%), 1-Benzyl-3,4-dimethoxycarbonyl-2-phenyl-pyrrolidin (79%) oder 3,4-Dinlethoxycarbonyl-1-(ethoxy-carbonyl-methyl )-2-phenyl-pyrrolidin (74%). 

Die Reaktion von Formaldehyd-(O-benzyl-oxim) mit einem Alkyl-lithium bei tiefer Tem-peratur fiihrt zum N-Lithium-Derivat eines N-Alkyl-O-benzyl-hydroxylamins, das bei der Umsetzung mit einem weiteren Alkyl-lithium das N-Lithium-Derivat eines Dialkylamins ergibt dieses wird ohne Isolierung mit einem Alkyl-halogenid zu einem Trialkylamin al-kyliert1. 

Zur selektiven N-Monoalkylierung von primaren Aminen kann man das Amin zunachst mit tert.-Butyl-chlor-dimethyl-silan N-silylieren, das isolierte N-Silyl-Derivat mit Butyl-lithium N-metallieren, anschlieBend mit einem Alkyl-halogenid umsetzen und schlieBlich die Silyl-Gruppe durch Behandlung mit trockenem Chlorwasserstoff abspalten1. 

Die Umalkylierung von cyclischen N-Methyl-aminen (z. B. 1-Methyl-piperidin, Morphin-Alkaloide) laBt sich in zwei Stufen durch Quaternisierung mit einem Alkyl-halogenid und Demethylierung des isolierten Quatemisierungsproduktes mit Natrium-benzolthiolat in siedendem Butanon/Acetonitril erreichen5 (vgl. S. 1221) ... 

In late 1975, Enders et al.156) started a research project directed towards the development of a new synthetic method for asymmetric carbon-carbon bond formation. A new chiral auxiliary, namely the (S)-proline derivative SAMP (137), was allowed to react with aldehydes and ketones to give the hydrazones (138), which can be alkylated in the a-position in an diastereoselective manner 157,158). Lithiation 159) of the SAMP hydrazones (138), which are formed in excellent yields, leads to chelate complexes of known configuration 160). Upon treatment of the chelate complexes with alkyl halogenides the new hydrazones (139) are formed. Cleavage of the product hydrazones (139) leads to 2-alkylated carbonyl compounds (140). 

It can be concluded from these experimental results that in alkaline media the 2-octyl nitrate behaves like a typical ester (Day and Ingold (50]). In neutral media, on the other hand, it behaves like an alkyl halogenide or like an ester of sulphuric acid. 

Interactions of C02 with alkyl halogenides or with compounds containing halogen-nitrogen bonds take place as dissociative electron captures. As a result, free radicals are formed according to Scheme 1-88 ... 

The processes involving the aziridine cycle are very diverse. For instance, reactions of alkylation by alkyl halogenides [63], bromoacetic acid derivatives [29, 30] and acetoxypropene [64], are known. The use of arylboronic acids for synthesis of TV-alkyl derivatives, e.g., compound 45, is described in [63] (Scheme 1.13). The one-step reaction at room temperature of aziridinyl ketones 46 with chloroacetamides 47 and sulfur in the presence of Et3N yields mono-thio-oxamidines 48 [65]. 

Alkyl halogenides were condensed on our bianion. This method may turn out to be useful for setting non-saturation in fatty-acid chains. 

In cathodic substitution anions are generated from neutral substrates E at the cathode, which react with alkyl halogenides present in the electrolyte to form substitution products E-R according to the scheme (Eq. (105) ) ... 

Nach Art einer Arbuzov-Reaktion reagieren aktivierte Alkyl-halogenide mit Phosphorig-saure-chlorid-diestern zu Phosphonsaure-chlorid-estem203 ... 

Diethyl dichlorolithiomethanephosphonate is readily prepared by Hal/Li exchange from diethyl trichloromethanephosphonate at temperatures below —85 °C and can be reacted in the presence of one equivalent of HMPT with a variety of alkyl halogenids 37). 

Molecules with two halogens in the a and cd positions yield a dication. A reaction analogous to reaction (68) was first described by Kennedy and Melby [259] who obtained the initiating carbocation by a reaction of alkyl halogenide with Et3Al or Et2AlCl. They have not prepared dication (multication) initiators directly nevertheless the route to them is evident. 

For alkylation of aromatic compounds with olefins, alcohols and alkyl halogenids, acidic zeolite catalysts may also be applied as it shown decads ago [1]. Alkylation of benzene with propene over acid catalysts yields isopropylbenzene (cumene) accompanied by formation of n-propylbenzene, di-isopropylbenzenes and propene oligomers as main by-products. 

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