From alkyl carbonates with

Silyl enol ethers are other ketone or aldehyde enolate equivalents and react with allyl carbonate to give allyl ketones or aldehydes 13,300. The transme-tallation of the 7r-allylpalladium methoxide, formed from allyl alkyl carbonate, with the silyl enol ether 464 forms the palladium enolate 465, which undergoes reductive elimination to afford the allyl ketone or aldehyde 466. For this reaction, neither fluoride anion nor a Lewis acid is necessary for the activation of silyl enol ethers. The reaction also proceed.s with metallic Pd supported on silica by a special method[301j. The ketene silyl acetal 467 derived from esters or lactones also reacts with allyl carbonates, affording allylated esters or lactones by using dppe as a ligand[302]... 

The stability of dialkylimidazolium cation-containing ionic liquids can be a problem even at moderate temperatures in the presence of some reagents or catalysts. For example, when CsF and KF were used in the ionic liquid [BMIM]PFg to perform a halogen exchange reaction in an attempt to replace Br from bromo-carbons with F , it was found that alkyl elimination from the [BMIM] cation took place, forming methyl imidazole, 1-butene, 1-fluorobutane, and other unidentified products at 150°C overnight 69). The fluoride ion acted as a base that promotes elimination or substitution processes. 

The simplest unfunctionalised carbon nucleophiles (15 and 17) are made from alkyl halides with various metals such as Li(0) or Mg(0) or by exchange with available organometallic reagents such as butyl-lithium (BuLi) in anhydrous coordinating solvents like ether (Et20) or THF (tetrahydro-furan 16). Enolates 11 are very important and will be discussed at length in later chapters. 

Various S-nucleophiles are allylated. Allylic acetates or carbonates react with thiols or trimethylsilyl sulfide (353) to give the allylic sulfide 354[222], Allyl sulfides are prepared by Pd-catalyzed allylic rearrangement of the dithio-carbonate 355 with elimination of COS under mild conditions. The benzyl alkyl sulfide 357 can be prepared from the dithiocarbonate 356 at 65 C[223,224], The allyl aryl sufide 359 is prepared by the reaction of an allylic carbonate with the aromatic thiol 358 by use of dppb under neutral condi-tions[225]. The O-allyl phosphoro- or phosphonothionate 360 undergoes the thiono thiolo allylic rearrangement (from 0-allyl to S -allyl rearrangement) to afford 361 and 362 at 130 C[226],... 

Dehydrohalogenation of alkyl halides (Sections 5 14-5 16) Strong bases cause a proton and a halide to be lost from adjacent carbons of an alkyl halide to yield an alkene Regioselectivity is in accord with the Zaitsev rule The order of halide reactivity is I > Br > Cl > F A concerted E2 reaction pathway is followed carbocations are not involved and rearrangements do not occur An anti coplanar arrangement of the proton being removed and the halide being lost characterizes the transition state... 

Because nitriles can be prepared from alkyl halides by nucleophilic substitution with cyanide ion the overall process RX RC=N RCH2NH2 leads to primary amines that have one more carbon atom than the starting alkyl halide... 

Dehydrohalogenation (Section 5 14) Reaction in which an alkyl halide on being treated with a base such as sodium ethoxide is converted to an alkene by loss of a proton from one carbon and the halogen from the adjacent carbon... 

Dialkyl peroxydicarboaates are used primarily as free-radical iaitiators for viayl monomer po1ymeri2ations (18,208). Dialkyl peroxydicarboaate decompositioas are accelerated by certaia metals, coaceatrated sulfuric acid, and amines (44). Violent decompositions can occur with neat or highly concentrated peroxides. As with most peroxides, they Hberate iodine from acidified iodides. In the presence of copper ions and suitable substrates, dialkyl peroxydicarbonates have been used to synthesi2e alkyl carbonates (44) ... 

Derivatives. Small amounts of alkyl quiaolines are present ia the tars resulting from the carbonization and Hquefaction of coal (111). Good yields of 4-methyl quinoline, 4,6-dimethyl quinoline [826-77-7], and 4,8-dimethyl quinoline [13362-80-6] are obtained from 4-(diethylamino)-2-butanone and the appropriate aniline. This approach is a promising addition to the traditional syntheses discussed eadier (112). Vlaylacetylene reacts with mercuric chloride and either aniline or -toluidine to yield 4-methyl- and 4,6-dimethyl quinoline, respectively (113). 

A chain mechanism is proposed for this reaction. The first step is oxidation of a carboxylate ion coordinated to Pb(IV), with formation of alkyl radical, carbon dioxide, and Pb(III). The alkyl radical then abstracts halogen from a Pb(IV) complex, generating a Pb(IIl) species that decomposes to Pb(II) and an alkyl radical. This alkyl radical can continue the chain process. The step involving abstraction of halide from a complex with a change in metal-ion oxidation state is a ligand-transfer type reaction. 

How would you synthesize the following compounds from acetylene and any alkyl halides with four or fewer carbons More than one step may be required. 

An aldehyde or ketone reacts with a phosphorus ylide to yield an alkene in which the oxygen atom of the carbonyl reactant is replaced by the =0 2 of the ylide. Preparation of the phosphorus ylide itself usually involves reaction of a primary alkyl halide with triphenylphosphine, so the ylide is typically primary, RCH = P Ph)3-This means that the disubstituted alkene carbon in the product comes from the carbonyl reactant, while the monosubstituted alkene carbon comes from the ylicle. 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

The synthesis of key intermediate 6 begins with the asymmetric synthesis of the lactol subunit, intermediate 8 (see Scheme 3). Alkylation of the sodium enolate derived from carboximide 21 with allyl iodide furnishes intermediate 26 as a crystalline solid in 82 % yield and in >99 % diastereomeric purity after recrystallization. Guided by transition state allylic strain conformational control elements5d (see Scheme 4), the action of sodium bis(trimethylsilyl)amide on 21 affords chelated (Z)-enolate 25. Chelation of the type illustrated in 25 prevents rotation about the nitrogen-carbon bond and renders... 

Kinetic stability of lithium and the lithiated carbons results from film formation which yields protective layers on lithium or on the surfaces of carbonaceous materials, able to conduct lithium ions and to prevent the electrolyte from continuously being reduced film formation at the Li/PC interphase by the reductive decomposition of PC or EC/DMC yielding alkyl-carbonates passivates lithium, in contrast to the situation with DEC where lithium is dissolved to form lithium ethylcarbonate [149]. EMC is superior to DMC as a single solvent, due to better surface film properties at the carbon electrode [151]. However, the quality of films can be increased further by using the mixed solvent EMC/EC, in contrast to the recently proposed solvent methyl propyl carbonate (MPC) which may be used as a single sol-... 

Filmers are based on primary, secondary, or tertiary monoamines or diamines and contain alkyl chains with from 8 to 22 carbons. The most prominent material is the 18-carbon-chain aliphatic monoalkylamine, octadecylamine (ODA). 

In all the desulphonylation reactions discussed in Sections III.B and III.C the sulphur is lost from the starting sulphone and is reduced in the process simultaneously, the former carbon-sulphur bond is either reduced to a C—H bond or is converted into a C=C bond. The reactions described in this section have the common thread that the sulphur atom is lost with reduction at sulphur, but the carbon atom is converted directly into a carbonyl group. Formally, these reactions offer a route from alkyl halides to aldehydes or ketones. 

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