Allylic derivatives

In addition to the preparation of l-alkenes, the hydrogenolysis of allylic compounds with formate is used for the protection and deprotection of carboxylic acids, alcohols, and amines as allyl derivatives (see Section 2.9). 

Formation of AllylEsters. AEyl esters are formed by reaction of aEyl chloride with sodium salts of appropriate acids under conditions of controEed pH. Esters of the lower alkanoic, alkenoic, alkanedioic, cycloalkanoic, benzenecarboxyEc, alkylbenzene carboxyEc, and aromatic dicarboxyEc acids maybe prepared in this manner (25). More information can be found about the reactivity of aEyl compounds (see Allyl alcohol and mono allyl derivatives). 

Treatment of 2-methylthiirane with t-butyl hydroperoxide at 150 °C in a sealed vessel gave very low yields of allyl disulfide, 2-propenethiol and thioacetone. The allyl derivatives may be derived from abstraction of a hydrogen atom from the methyl group followed by ring opening to the allylthio radical. Percarbonate derivatives of 2-hydroxymethylthiirane decompose via a free radical pathway to tar. Acrylate esters of 2-hydroxymethylthiirane undergo free radical polymerization through the double bond. 

Claisen rearrangement of the allyl enol ether of tnfluoroacetylacetone gives a C-allylated derivative [123] (equation 106)... 

The 2,2 -bis(phenylthiomethyl) dispiroketal (dispoke) derivative is cleaved by oxidation to the sulfone, followed by treatment with LiN(TMS)2. The related bromo and iodo derivatives are cleaved reductively with LDBB (lithium 4,4 -di- -butylbiphenylide) or by elimination with the P4- -butylphosphazene base and acid hydrolysis of the enol ether. The 2,2-diphenyl dispiroketal is cleaved with FeCl3 (CH2CI2, rt, overnight)." The dimethyl dispiroketal is cleaved with TFA, and the allyl derivative is cleaved by ozonolysis followed by elimination. ... 

Allylation of the 7-hydroxyquinoline derivative 242 with allyl bromide gave the corresponding 7-allyl ether 243 which underwent Claisen rearrangement to give the 8-allyl derivative 244. Acylation and subsequent bromination afforded the dibromopropyl derivative 245. Treatment of 245 with KOH/EtOH gave 8-hydroxypyrroloquinoline 246 that was methylated with methyl iodide to afford 247 (91JOC980) (Scheme 44). 

Bromination of the diphenyl indole derivative 316 with bromine in DMF or trimethylammonium bromide afforded the 7-bromo derivative 317. Reaction with allyl bromide or its derivatives gave A-allyl derivatives 318 that upon cyclization with palladium acetate gave 7,9-dimethoxy-l,2-diphenylpyrrolo[3,2,l-// ]quinoline derivatives 319 (92T7601) (Scheme 57). 

The addition of carbene to a 3-(halopropyl)-5//-dibenz[7>./]azepine 5 (X = Cl, Br) in a Simmons—Smith reaction is more complex and results in a mixture of the tetracycle 6 (6%), its cyclopropano derivative 7 (48 %), the 5-allyl derivative 8 and the (cyclopropyl)methyl compound 9, the latter two products in a combined yield of 12%.31... 

The corresponding zirconium allyl derivatives have also been investigated6,7, but, in general, do not have any particular advantages over the titanium reagents. In addition, the starting materials are often more expensive and more difficult to purify. 

Disubstituted allyl derivatives, bearing hetero substituents have also been investigated86. As observed for the titanium(IV) counterparts, the regio- and stereochemical features depend largely on the type of substituents. 

The breakthrough was achieved with the creation of dialkoxy(tj5-cyclopentadienyl)titanium(IV) chlorides derived from sterically hindered chiral alcohols11 35,35a 36. Allyl derivatives 8 and 10, prepared in situ from complexes 7 and 9, have sufficient stability and reactivity. 

Lewis acid induced alkylation of 4-alkoxy-3,5-dialkyl-2-oxazolidinones with allylsilanes gives the 4-allyl derivatives with complete irons stereoselectivity114,115. Cleavage of the oxazolidi-none ring with aqueous sodium hydroxide in ethanol leads to vicinal twP -aminoalkanols. 

The reactivity of T8[OSiMe2H]g is dominated by its capacity to undergo hydrosilylation reactions with a wide variety of vinyl and allyl derivatives (Figure 30) that have subsequently mainly been used as precursors to polymers and nanocomposites by the introduction of reactive terminating functions as shown in Table 19. For example, T8[OSiMe2H]g has been modified with allyglycidyl ether, epoxy-5-hexene, and 1,2-cyclohexene-epoxide to give epoxy-terminated FOSS. These have then been treated with m-phenylenediamine, with polyamic acids or... 

Chiral pyridine-based ligands were, among various Ar,AT-coordinating ligands, more efficient associated to palladium for asymmetric nucleophilic allylic substitution. Asymmetric molybdenum-catalyzed alkylations, especially of non-symmetric allylic derivatives as substrates, have been very efficiently performed with bis(pyridylamide) ligands. 

COCH3 >—CN >—COOR >—Cl >—CH2Y >—OCOCH3 >—OR. The effect of a second 1-substituent is roughly additive. 2-Chlorobutadiene and 2,3-dichlorobutadiene [not included in Table XX] are the most reactive monomers examined. A methyl group usually increases reactivity (methyl methacrylate >methyl acrylate, methacrylonitrile > acrylonitrile, methal-lyl>allyl derivatives) and two chlorine atoms are nearly as effective as a carbalkoxy group. 

Pd Alkenes (including a,(5-unsaturated carbonyls, styrenes, allyl derivatives), nitrotoluene, diphenylacetylene... 

Allylic derivatives are particularly important in the case of boranes, silanes, and stannanes. Allylic boranes effect nucleophilic addition to carbonyl groups via a cyclic TS that involves the Lewis acid character of the borane. 1,3-Allylic transposition occurs through the cyclic TS. 

Alkyl, aryl, and allyl derivatives of boron can be prepared directly from the corresponding halides, BF3, and magnesium metal. This process presumably involves in situ generation of a Grignard reagent, which then displaces fluoride from boron.2... 

Another computational study examined the effect that the boron ligands might have on the reactivity of allyl derivatives.50 The order found is shown below and is related to the level of the boron LUMO. The dominant factor seems to be the ir-donor capacity of the ligands. The calculated order is consistent with experimental data.51... 

Oxygenated allylic derivatives of (Ipc)2BH also show excellent diastereoselectivity. 

However, the affinity of 43 was higher than that of the allylic derivative 72 and near to that of codeine, though 5-fold less (74). Recently, some naturally occurring hasubanan alkaloids have been submitted to screening for antitumor activity, but the results, as far as we know, remain obscure. 

The method can also be performed in an iterative manner [367],andthescopeofthe one-pot process can be broaden by replacing Bu3SnH by its allylic derivative Bu3SnAl-lyl, thus allowing tbe introduction of an allyl group instead of a hydrogen [365],... 

Substituents in the allyl group of a catalyst have a marked effect on the polymerization efficiency (9,12). This is shown in Table IV for the polymerization of ethylene with chromium and zirconium allyls and for the polymerization of methyl methacrylate with chromium allyls. Introducing a methyl group into the allyl ligand increases the activity by a factor of 2 to 7. In some polymerizations of ethylene Cr(2-Me-allyl)3 compounds are ten times more effective than the simple allyl derivatives. The introduction of... 

The structures under consideration are indicated in Inserts VI and VII. Such radicals are usually secondary products of radiolysis, formed, for example, by extraction of hydrogen from a R2C(H)-precursor. However, closely related radicals can be formed, for example, by electron-loss from vinyl- or allyl- derivatives (66,67) or from substituted aromatic cations (68,69) [see, for example, VIII-X]. 

Dialkylindolines and 1,3-dialkylindoles are formed in poor yield (<10%) from the reaction of ethyl- or phenymagnesium bromide with 2-chloro-N-methyl-N-allylaniline in the presence of catalytic quantities of (bistriphenylphosphine)nickel dichloride.72 In a modification of this procedure, the allyl derivatives can be converted by stoichiometric amounts of tetrakis(triphenylphosphine)nickel into 1,3-dialkylindoles in moderate yield72 (Scheme 43) an initial process of oxidative addition and ensuing cyclization of arylnickel intermediates is thought to occur. In contrast to the nickel system,72 it has proved possible to achieve the indole synthesis by means of catalytic quantities of palladium acetate.73 It is preferable to use... 

The study of solvated alkali metal allyl species remains a complex topic due to a variety of reorganization processes. Structural data on alkali metal allyl derivatives include [G3H5Li(TMEDA)] 133,139 where solvated lithium ions act as... 

Calculations of alkali metal allyl derivatives involving all alkali metals (Li-Cs) indicate a preferred geometry with the metal symmetrically bound in a predominantly electrostatic manner to all three carbon atoms.143 Solution studies of allyllithium in ether indicate the compounds to be highly aggregated in THF complex dynamic behavior is observed. 

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