Butyl iodide alkylation with

Mel, CH3CN morpholine or diethylamine, methanol, 76-95% yield. These conditions also cleave tlie 4 -pyridyl derivative. The Pet ester is stable to the acidic conditions required to remove the BOC and r-butyl ester groups, to the basic conditions required to remove the Fmoc and Fm groups, and to hydrogenolysis. It is not recommended for use in peptides that contain methionine or histidine since these are susceptible to alkylation with methyl iodide. 

Primary halides are more reactive than secondary compounds quaternary salt formation does not occur with tertiary halides, elimination always occurring to give the hydriodide and an olefln, Also, the larger the alkyl group the slower is the reaction this is shown by the very slow reaction of dodecyl bromide with quinoline, and even butyl iodide is much slower to react than methyl iodide. The longer chain primary halides commonly undergo elimination rather than cause quaternization for example, n-octyl and cetyl iodides give only the hydriodides when heated with 9-aminoacridine. ... 

Certain of the monoalkylated ethyl phenylacetates have been further alkylated with alkyl and aralkyl halides to produce the corresponding disuhstituted phenylacetic esters.4 Ethyl 2-phenyl-propanoate has been alkylated by methyl iodide to give pure ethyl 2-methyl-2-pheny]propanoate in 81% yield. Similarly, the alkylations of ethyl 2-phenylhexanoate with methyl iodide, M-butyl bromide, and benzyl chloride gave the corresponding pure dialkylated products in 73%, 92%, and 72% yields, respectively. 

E Selective Wittig reagents. The reaction of 1 with lithium in THF provides LiDBP, which on reaction with an alkyl halide (2 equiv.) and NaNH2 in THF gives a salt-free ylide such as 2 or 3, formed by reaction with ethyl iodide or butyl iodide, respectively. These ylides react readily with aldehydes at —78°, but the intermediate oxaphosphetanes are unusually stable and require temperatures of 70-110° for conversion to the phosphine oxide and the alkene, which is obtained in E/Z ratios of 6-124 1. Highest (E)-selectivity is observed with a-branched aldehydes. 

Quite similar results have been found recently in the reaction of the cobalt(i) form of vitamin B,2 (Bus) with alkyl halides with n-butyl iodide, bromide and chloride, ethyl bromide and benzyl chloride the representative data point of vitamin B s falls several orders of magnitude above the outer sphere dissociative electron-transfer line (Walder, 1989). 

The H.T.-Cl can also be a catalyst for alkyl iodide production in toluene. Thus, benzyl iodide could be obtained by the reaction of benzyl chloride (33 mmol) with butyl iodide (33 mmol) at 373 K (Table 1). 

Stereoselective alkylation with aliphatic bromides and iodides of the Schiff bases of tert-butyl glycinate with (—)-(15,25,55)-2-hydroxypinan-3-one or (+)-(lR,2R,5R)-2-hydroxy-pinan-3-one 150 was reported to produce lipidated amino acids as d- and L-enantiomers in 80 to over 90% ee. 151 Similarly, the asymmetric synthesis of a derivative of arachidonic acid (4) has also been reported. The pure enantiomer was obtained via regioselective functionalization of a chirally pure glutamic acid. 152 ... 

Polymer supports different from polystyrene show different response to % RS in triphase catalysis of nucleophilic displacements. Poly(4-vinylpyridines) 66-71 % alkylated with C8, C12, and C16 chains (6) give high yields of cyanide displacement on 1-bromooctane and on 1-iodooctane and of bromide/iodide exchange of the 1-halooctanes81,87). An 81.6% RS n-butyl-quaternized poly(4-vinylpyridine) (6)... 

With benzyl, allyl, and primary alkyl halides the yields are 72-90% they are low with isopropyl iodide (34%) with tert-butyl bromide no reaction occurred. This behavior is consistent with results already reported. Alkylation of anions often give poor results with secondary alkyl halides and no alkylation with tertiary alkyl halides. 

Regioselective alkylation of a methyl ketone Even though the kinetic enolate of 2-heptanone consists of a mixture of terminal and internal enolates in the ratio 87 13, benzylation in DME results in preferential internal alkylation. Regioselective benzylation at the terminal position can be enhanced by addition of various ligands such as benzo-14-crown-4 and DMF, but HMPT is the most effective ligand, resulting in a ratio of terminal to internal benzylation of 11 1. The three ligands also increase the rate of alkylation. The same effect, but less marked, is observed in alkylation with the less reactive electrophile butyl iodide. 

Buchachenko (1974) has advanced another theory. He based his reasoning on the absence of the CIDNP signals for the reaction of //-butyl iodide with t-butyl lithium conducted in ether at -70°C. The halogen and metal quickly exchange under these conditions, but the C—C bond does not form. In contrast to the preceding scheme, Buchachenko s theory assumes that the radicals produced form complexes with the alkyl lithium associates. Alkyl... 

No reaction of unmilled aluminum powder with alkyl halides was observed during 10 hours of contact. When aluminum was milled with stainless steel balls in a stainless steel pot under helium at room temperature in the presence of butyl iodide for 8 min, an exothermic reaction was initiated and no more activation was required for the continuation of the reaction. 

Notice that for SN2 substitution, the alkyl halide came from the less sterically hindered group. For SN1 type reactions, the alkyl halide forms from the fragment of the original molecule that forms the more stable cation. Thus, the reaction of t-butyl ethyl ether with HI gives t-butyl iodide and ethyl alcohol. The following mechanism occurs ... 

As outlined by Roush and Walts,62 sulfoxide 21 was converted to the corresponding dianion with lithium diisopropylamide (LDA) and alkylated with n-butyl iodide to provide a diastereomerically complex mixture that was then converted directly to 2-butyl-3R-methylcyclohex-2-en-l-one (50% yield, 6 1 (P oc) mixture at C-2) upon thermolysis. We found that sulfoxide 21 could be alkylated with 2-(2-bro-moethyl)-2,5,5-trimethyl-1,3-dioxane63 and that the resultant complex mixture could be desulfurized with aluminum amalgam to furnish desired ketone 17 in 40-50% yield as 9 1 (P a) mixture at C-2. Surprisingly, alkylation of this sulfoxide dianion was not improved using 2-(2-iodoethyl)-2,5,5-trimethyl-l,3-dioxane17 in place of the bromide. 

This is a typical SN2 reaction (1) kinetics usually display clean second order (b) when the reagent is chiral, inversion of configuration occurs at the asymmetric carbon (71 ACS 18) when the alkylating reagent is tertiary (t-butyl iodide) or even secondary (i-Pr iodide), E2 elimination competes with aliphatic substitution (55JA1715 76AJC1745). 

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