1-Bromoheptane alkylation with

A more recent synthesis of 197 [365] is shown in Fig. 9. Enders introduced the stereogenic centre of (S)-lactic acid into the crucial position 10 in 197. The vinylsulfone B, readily available from lactic acid, was transformed into the planar chiral phenylsulfonyl-substituted (q3-allyl)tetracarbonyliron(+l) tetra-fluoroborate C showing (IR,2S,3 )-configuration. Addition of allyltrimethyl silane yielded the vinyl sulfone D which was hydrogenated to E. Alkylation with the dioxolane-derivative of l-bromoheptan-6-one (readily available from 6-bro-mohexanoic acid) afforded F. Finally, reductive removal of the sulfonyl group and deprotection of the carbonyl group furnished 197. A similar approach was used for the synthesis of 198 [366]. 

Alkylation of isoprene at the methyl group was achieved through the reaction of the corresponding metal derivative (fert-BuOK-lithium tetramethylpiperidine, THF) with 1-bromoheptane (60% yield).257 Regioselective monoalkylation of isoprope-nylacetylene can be performed in high yields through the dilithium derivative 258... 

Nitro compounds can be alkylated and are good at conjugate addition (chapter 21) so the products of these reactions can be used to make aldehydes, ketones and amines. A simple synthesis of octanal5 shows that these methods can work very well indeed. Alkylation of nitromethane with bromoheptane gives the nitro-compound 11. Formation of the anion 12 and oxidation with KMnC>4 gives octanal in 89% yield. This chemistry gives us the disconnection to an alkyl halide and a carbonyl anion. The anion 12 is an acyl anion equivalent and we shall need these in the next chapter. 

An efficient synthesis of the azocane cycle 65 is accomplished by N-alkylation of 2-nitrobenzenesulfonamide 64 with 1,7-bromoheptane and subsequent cyclization of the sulfonamide thus obtained (Scheme 41) <2002T6267, CHEC-III (14.01.5.3)20>. 

The first route was rather straight forward introducing first the nitrogen containing side chain by reacting the epoxide with methylamine in methanol at 120 °C under pressure to the amino-alcohol 215 and N-alkylation of this intermediate with 1-bromoheptane in ethanol to the tertiary amine 216. This same product was prepared directly by reaction of the epoxide with N-methylheptylamine in ethanol with a catalytic amount of hydrochloric acid at 120 °C under pressure. O-alkylation was performed according to the method used by J. Fried69) that is reaction of 216 with tert. butyl-oj-iodohexanoate (NaH in DMSO). Compound 217 was charac-... 

The fundamental theory of phase transfer catalysis (PTC) has been reviewed extensively. Rather than attempt to find a mutual solvent for all of the reactive species, an appropriate catalyst is identified which modifies the solubility characteristics of one of the reactive species relative to the phase in which it is poorly solubilized. The literature on the use of PTC in the preparation of nitriles, halides, ether, and dihalocarbenes is extensive. Although PTC in the synthesis of C- and 0-alkylated organic compounds has been studied, the use of PTC in polymer synthesis or polymer modification is not as well studied. A general review of PTC in polymer synthesis was published by Mathias. FrecheE described the use of PTC in the modification of halogenated polymers such as poly(vinyl bromide), and Nishikubo and co-workers disclosed the reaction of poly(chloromethylstyrene) with nucleophiles under PTC conditions. Liotta and co-workers reported the 0-alkylation of bituminous coal with either 1-bromoheptane or 1-bromooctadecane. Poor 0-alkylation efficiencies were reported with alkali metal hydroxides but excellent reactivity and efficiencies were found with the use of quaternary ammonium hydroxides, especially tetrabutyl- and tetrahexylammonium hydroxides. These results are indeed noteworthy because coal is a mineral and is not thought of as a reactive and swellable polymer. Clearly if coal can be efficiently 0-alkylated under PTC conditions, then efficient 0-alkylation of cellulose ethers should also be possible. 

Now, let s draw the forward scheme. In the presence of peroxides, the reaction of 1-pentene with HBr produces 1-bromopentane (via anfe -Markovnikov addition). Subsequent reaction with acetylide [produced from ethylene as shown by bromination (Br2), double elimination and deprotonation (excess NaNH2)] provides 1-heptyne. Reduction to the alkene (H2 / Lindlar s catalyst) followed by anP-Markovnikov addition (HBr / peroxide) yields 1-bromoheptane. This primary alkyl bromide can then undergo an Sn2 reaction when treated with acetylide (prepared above), giving the... 

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