Diaryl allyl alcohol

Iron-catalysed trifluoromethylation with concomitant 1,2-migration of an aryl group starting from diaryl allyl alcohol has been reported to give a-substituted-j0-trifluoromethyl carbonyl compounds (Scheme 86). ... 

Copper-catalysed trifluoromethylation-initiated radical 1,2-aryl migration (neophyl rearrangement) in a,a-diaryl allylic alcohols to give a-aryl / -trifluoromethyl ketones occurs with preferential migration of electron-deficient aryl groups over electron-rich ones, supporting a radical mechanism which has been confirmed by density functional calculations (Scheme 120). ... 

Nucleophilic Displacement. PhTMS-BF3 0Et2 system has been shown to be useful in the transformation of allylic alcohols to allylic sulfides (eq IS). Preparation of unsymmetrical diaryl sulfides can be achieved by reaction of arenediazonium tetraflu-oroborates with PhSTMS (eq 19). In some cases, addition of cupric sulfide increases the yield of the diaryl sulfides. The use of (phenylthio)trimethylsilane as a coupling partner in palladium catalyzed reactions with aUyl carbonates (eq 20) and aryl iodide (eq 21) has been explored. ... 

Silver-catalysed phosphonation of ot,a-diaryl allylic alcohols (325) provided a series of y-ketophosphonates (326). The mechanistic study indicated that the reaction was initiated by addition of P-radicals to the alkene followed by 1,2-migration of an aryl group to form the C(Ar)-C(sp ) bond (Scheme 91) ... 

In 2003, Sigman et al. reported the use of a chiral carbene ligand in conjunction with the chiral base (-)-sparteine in the palladium(II) catalyzed oxidative kinetic resolution of secondary alcohols [26]. The dimeric palladium complexes 51a-b used in this reaction were obtained in two steps from N,N -diaryl chiral imidazolinium salts derived from (S, S) or (R,R) diphenylethane diamine (Scheme 28). The carbenes were generated by deprotonation of the salts with t-BuOK in THF and reacted in situ with dimeric palladium al-lyl chloride. The intermediate NHC - Pd(allyl)Cl complexes 52 are air-stable and were isolated in 92-95% yield after silica gel chromatography. Two diaster corners in a ratio of approximately 2 1 are present in solution (CDCI3). 

Carbon monoxide rapidly inserts into the carbon—zirconium bond of alkyl- and alkenyl-zirconocene chlorides at low temperature with retention of configuration at carbon to give acylzirconocene chlorides 17 (Scheme 3.5). Acylzirconocene chlorides have found utility in synthesis, as described elsewhere in this volume [17]. Lewis acid catalyzed additions to enones, aldehydes, and imines, yielding a-keto allylic alcohols, a-hydroxy ketones, and a-amino ketones, respectively [18], and palladium-catalyzed addition to alkyl/aryl halides and a,[5-ynones [19] are examples. The acyl complex 18 formed by the insertion of carbon monoxide into dialkyl, alkylaryl, or diaryl zirconocenes may rearrange to a r 2-ketone complex 19 either thermally (particularly when R1 = R2 = Ph) or on addition of a Lewis acid [5,20,21]. The rearrangement proceeds through the less stable... 

Other unsaturated substrates arylated by various diaryl iodonium salts included butenone, acrylic acid, methyl acrylate and acrylonitrile [46]. Allyl alcohols with diaryliodonium bromides and palladium catalysis were arylated with concomitant oxidation for example, from oc-methylallyl alcohol, aldehydes of the general formula ArCH2CH(Me)CHO were formed [47]. Copper acetylide [48] and phenyl-acetylene [49] were also arylated, with palladium catalysis. 

Oxidation of alcohols. Alcohols can be oxidized to carbonyl compounds by f-butyl hydroperoxide (slight excess) and a diaryl diselenide (0.1-0.5 equiv.). Diphenyl diselenide is satisfactory, but bis(2,4,6-trimethylphenyl) diselenide is generally more satisfactory. The method is particularly efficient for benzylic and primary allylic alcohols (12 hours, 87-100% yield) oxidation of saturated alcohols, primary and secondary, requires 4-17 hours, but still proceeds in excellent yield. 

Several further modifications of this reaction have been reported more recently [250-252,604]. In particular, a multicomponent reaction of allenes 544, diaryl diselenides, (diacetoxyiodo)benzene and alcohols or acids affords 3-functionalized 2-arylselenyl-substituted allyl derivatives 545 in moderate yields (Scheme 3.216) [250],... 

TMSCl is essential as a promoter in a low-valent vanadium-catalysed reductive cyclotrimerization of aliphatic aldehydes, producing 1,3-dioxolanes (equation 4). It is also an essential component in the zinc-induced intramolecular imine cross coupling of diarylidene sulphamides subsequent cleavage provides a route to unsymmetiical l,2-diaryl-l,2-diaminoethanes (equation 5). It acts as an activating agent in the samarium-promoted cyclopropanation of allylic and a-allenic alcohols. 

Oxidative Methods.—Oxidation of Alcohols. Benzoyl peroxide catalysed by nickel(ii) bromide gives high yields of aldehydes and ketones from the corresponding alcohols. Similar yields are obtained with t-butyl hydroperoxide catalysed by diaryl diselenides, a method particularly recommended for benzylic or allylic alcohols. Ketones are obtained from secondary alcohols using hydrogen peroxide catalysed by molybdenum or tungsten peroxo-complexes/ and nickel peroxide has been employed to prepare a-allenic aldehydes and ketones from allenic alcohols. ... 

Diels-Alder reactions, 133, 135 epoxidation, 69-72, 516 grafting on polyethylene, 462 hydroformylation, 44 hydrogenation, 41, 42 isomerization catalysts, 133, 484 isomerization during polymerizations, 484 isomerization kinetics, 484 isopropyl alcohol radical reaction, 207 MA copolymerization, 532, 534, 541 Michael reactions, 63-66 nitrone adducts, 224, 225 olefin copolymerization, 288 olefin ene reactions, 162 phenanthrene adducts, 181 plasticizers use, 14 production—synthesis, 14, 78-81 radical copolymerization, 270, 275-277, 307, 315, 317, 333, 345, 365, 379 radical polymerization, 239, 264, 287 reaction with allyl alcohol, 46 reaction with sodium bisulfite, 53 styrene copolymerization, 365, 483 tetraalkyl methylenediphosphonate adduct, 66 transesterification, 46 /7-xylylene copolymerization, 359 dialkyl stannyl, PVC stabilizer, 275 diaryl, synthesis from MA, 80 pyridinium, betaine intermediate, 216... 

Homoallylic alcohol 9 is readily prepared by palladium-catalyzed directed cyanoboration followed by Suzuki-Miyaura cross-coupling (Scheme 5.15) [15]. Palladium-catalyzed allyl transfer from 9 to aryl bromide results in removal of the hydroxymethyl directing group and concomitant formation of 3,4-diaryl-2-butenenitrile albeit the lack of regio- and stereospecificity. The overall transformation proposes a concept of intramolecular reaction with a carbon tether removable through retro-allylation. 

C-0 Bond Formation. A simple and mild method for the coupling of aryl iodides and aliphatic alcohols catalyzed by copper iodide which does not require the use of aUcoxide bases has been described. The reaction can be performed in neat alcohol or in toluene as solvent with catalytic quantities of Cul and 1,10-phenanthrohne, and 2 equiv of CS2CO3. This methodology was successfully applied to the formation of allyl vinyl ethers with tetramethyl-l,10-phenanthroline as the ligand. iVAl-Dimethyl glycine is also a good ligand for this copper iodide-catalyzed Ullmann-type diaryl ether synthesis between phenols... 

Suitable mechanisms have been proposed following determination of the kinetic and activation parameters for oxidation of 2-naphthol and cyclic ketones by nicotinium dichromate some a-amino acids by tripropylammonium fluorochromate " distyryl ketone by quinaldinium fluorochromate methanol by benzyltriethylammonium chlorochromate catalysed by 1,10-phenanthroline substituted benzyl alcohols by tetraethylammonium bromochromate L-cysteine by pyridinium bromochromate lactic acid and 3,5-dimethyl-2,6-diaryl piperidin-4-one oximes by pyridinium chlorochromate allyl alcohol by IDC benzophenoxime by bispyridine silver(I) dichromate and alkyl phenyl sulfides by cetyltrimethylammonium dichromate. A non-linear Hammett plot obtained for the oxidation of substituted benzyl alcohols by IDC has been attributed to the operation of substituent effect on two steps of the proposed mechanism. " Kinetic and activation parameters for oxidation of o-toluidine and of A-methyl-2,6-diphenyl piperidin-4-one oxime and its 3-alkyl derivatives by sodium dichromate have been determined and suitable mechanisms have been suggested. Micellar catalysis in the 1,10-phenanthroline-promoted chromic acid oxidation of propanol... 

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