Naphthyl derivatives

Polyphosphoric acid is a commonly used catalyst for this reaction however, in some cases a mixture of hydrogen bromide/acetic acid gives better results. Acylation of the S-phenyl-, V-(4-tolyl)- or S-(l-naphthyl)-substituted thiobenzenepyruvic acids 3a-c affords the corresponding dibenzo[A,/]thiepins in satisfactory yields, while reaction of the S-(4-methoxyphenyl) or S-(2-naphthyl) derivatives fails to provide any thiepin.60 The intramolecular Friedel-Crafts acylation of 2-(arylsulfanyl)benzeneacetic acids also yields the corrresponding dibenzothiepins in this case the use of hydrogen fluoride sometimes results in purer products.38 The applicability of this method is restricted to the synthesis of stable bisannulated thiepins. 

The naphthyl derived ligand, (5)-1-mcthyl-2-[(l-naphthylamino)methyl]pyrrolidine (4) is especially effective in the stereoselective additions of (Z)-l-cthylthio-l-trimethylsilyloxy-l-propene to aldehydes. Thus, quantitative formation of. yyn-adducts is achieved, in addition to high reagent-induced stereoselectivity (>98% ee for the 3-hydroxy thioester products)23 32. 

The proline derived diamines 2 and 4 (vide supra) are also suitable chiral additives in enantiose-lective additions of a-unsubstituted enolates. Best results are obtained with the naphthyl derivative, as demonstrated in the tin(II) triflate mediated addition of the O-silylketene thio-acetal l-toT-butylthio-l-trimethylsilyloxyethane to aldehydes which delivers 3-hydroxythio esters in optical purities of up to 95% ee and chemical yields between 50 and 90 %24... 

As well as phenyl derivatives, other products have been prepared by hydrolysis of alkoxysilanes such as cyclohexenyl or naphthyl derivatives as well as heterocyclic compounds based on thienyl rings (Table 31, entries 28-33). Few practical applications have been reported for this type of compound, except for the styryl compound T81C6H4-A-CFI = CH2]s, and the fluorinated TslCeFsJs which have been used in polymer blending (Table 31, entries 13 and 28). ... 

The first P-chiral hydroxy phosphoryl compounds that were enzymatically resolved into enantiomers were o-hydroxyaryl phosphines and their oxides 75. The resolution was achieved via enzyme-assisted hydrolysis of their O-acetyl derivatives 74, the most effective enzymes being CE and Upase from C. rugosa (CRL) (Equation 35). The highest enanfioselectivity was observed in the case of naphthyl derivatives (Equation 36), having a P=0 moiety. ... 

On heating with sodium acetate and acetic anhydride under nitrogen, berberine (15) gave the naphthyl derivatives 61 and 62. The reaction proceeds as indicated in Scheme 15. Similar treatment of dehydroprotoberberine (54) gave the aromatized naphthylisoquinoline 63 owing to the presence of the additional double bond in ring B (52,53). 

We may envisage the two modes of chain inclusion as sketched in Fig. 13 in one, a linear stack of CDs is threaded by two separate chains, and in the other it is threaded by one folded chain. To see which is more likely to occur, Harada and coworkers prepared monosubstituted naphthyl derivatives of PEG (PEG-2N) and found that the emission spectra for their complexes with y-CD were... 

Addition of triethylamine to the oxazaborolidine reaction system can significantly increase the enantioselectivity, especially in dialkyl ketone reductions.79 In 1987, Corey et al.80 reported that the diphenyl derivatives of 79a afford excellent enantioselectivity (>95%) in the asymmetric catalytic reduction of various ketones. This oxazaborolidine-type catalyst was named the CBS system based on the authors names (Corey, Bakshi, and Shibata). Soon after, Corey s group81 reported that another fi-methyl oxazaborolidine 79b (Fig. 6-6) was easier to prepare and to handle. The enantioselectivity of the 79b-catalyzed reaction is comparable with that of the reaction mediated by 79a (Scheme 6-36).81 The -naphthyl derivative 82 also affords high enantioselectivity.78 As a general procedure, oxazaborolidine catalysts may be used in 5-10 mol%... 

The second point is that the naphthyl derivatives give higher barriers to rotation... 

FIGURE 25. Solid-state structures of hthium naphthyl derivatives... 

Admittedly, we are not surprised that the decomposition enthalpies of styrene and 2-vinylnaphthalene peroxides are close to each other, as are those of the isomeric isopropenyl species. There is a rather rehable constant enthalpy of formation difference between phenyl and naphthyl derivatives, and as a corollary, a near-equaUty of the enthalpies of formation of 1- and 2-naphthyl derivatives, cf. the combined calculational and calorimetric studies of M. V. Roux, M. Temprado, R. Notario, S. P. Verevkin, V. N. Emel yanenko, D. E. DeMasters and J. F. Liebman, Mol. Phys., 102, 1909 (2004) and references cited therein. It is perhaps more surprising that the a-methyl group on the unsaturated moiety (vinyl -> isopropenyl) causes such a small change. 

Condensation of the alkoxynaphthyldihydrooxazoles with 2-methoxy-l-naphthyllithium, prepared by bromine-lithium exchange, did not lead to the same product as the corresponding reactions with the magnesium compound, but, unexpectedly, to a rearranged isomeric 1 -bi-naphthyl derivative with high enantiomeric excess28. 

Simultaneous use of the Fricdcl-Craft catalytic properties of anhydrous hydrogen fluoride and its fluorinating activity in Cl-F replacement reactions has been utilized in the synthesis of numerous trifluoromethyl aromatics (phenyl, biphenyl, and naphthyl derivatives).246 247 The process is based on the action of carbon tetrachloride/hydrogen fluoride (excess) on aromatics, for example, formation of 16,246 17,246 18 and 19.246... 

As would be expected, vinyl and naphthyl derivatives are observed to have nearly the same dipole moments as the phenyl derivatives... 

Methyl- or 2-ethyl-benzo[Z> ]thiophenes are conveniently prepared by treatment of 2-benzo[6]thienyllithium with the appropriate alkyl sulfate <70AHC(11)177). Clemmensen or Wolff-Kishner reductions of the 2-acylbenzo[Z>]thiophenes are useful, but since acylation produces a mixture of the 2- and 3-acyl isomers (Section 3.14.2.4), these must be separated. Cyclization of phenyl phenacyl sulfide with hydrofluoric acid leads exclusively to 2-phenyl-benzo[6]thiophene, and 3-phenylbenzo[6]thiophene can be rearranged to the 2-isomer in hydrofluoric acid (Section 3.15.2.3.2). Aromatization of 2-cycIohexenylbenzo[6]thiophene, obtained by condensation of the 2-lithio reagent with cyclohexanone, gives 2-phenyl-benzo[6]thiophene, and the reaction is adaptable to the 2-(l-naphthyl) derivative also. 

The 2-aminophenoxy triazine (50) readily undergoes the Smiles rearrangement in base (equation 23) (70JHC981), or photochemically (70TL1467). Budziarek reported a similar reaction with the naphthyl derivative (51 Scheme 37) (7lJCS(C)74>. 

The a- and /3-naphthyl derivatives, Compounds 24 and 25, as well as Compound 26 were prepared from the bis-tosylate (7) and the corresponding lithium diarylphosphide. 

Pyridines attached to another aryl or hetaryl ring also introduce the possibility of restricted rotation about the biaryl linkage. Typically, this requires three substituents at the or/ o-positions on the biaryl as in the case of the naphthyl derivatives 48, where the stereochemistry is determined by NMR spectroscopy <2001J(P1)1785>. Other methods of determining conformations, such as the comparison of experimental and computed circular dichroism spectra, have been applied to the related Yaoundamine alkaloids such as the derivative 49 <1997T2817>. 

Inclusion complexes between the 2-naphthyl derivatives and y-cyclodextrin have been studied as well [39]. In this cyclodextrin system, it is possible to include two solute molecules within a single cavity. This association mode leads to the observation of exciton CD bands in the absorption spectrum, and excimer bands in the fluorescence spectrum. 

In fact, the reaction proceeded as expected [23]. Thus, by heating the l-[o-(l-alkynyl)phenyl]cyclopropanol complexes 36-Co2(CO)6 in refluxing 2-propanol, 2,3-dihydro-1-naphthalenone derivatives 37 are obtained as a mixture of (Aland (Z)-isomers in moderate yield accompanied by a substantial amount of an ethyl ketone derivative formed by ring opening of the cyclopropanol moiety. Furthermore, when an analogous naphthyl derivative 38 was employed, the reaction proceeded cleanly and the 2,3-dihydrophenanthren-l-one derivative 39 was obtained in 83 % yield (Scheme 17). The obvious difference in reactivity between phenyl and naphthyl derivatives is probably due to the presence of hydrogen at the peri position of the latter. To avoid steric repulsion between the alkyne-Co2(CO)6 moiety and this hydrogen, the molecule adopts a conforma-... 

The 1- and 2-naphthoxide ions also reacted with z -bromobenzonitrile261, p-iodoanisole262 and 1- and 2-iodo- substituted naphthalenes262,263. In the reaction of 1-naph-thoxide ions a mixture of 2- and 4-monosubstituted naphthyl derivates (192 and 193, respectively) together with the 2,4-disubstituted compounds 194 were observed (equation 139). Thus,/7-bromobenzonitrile, 1-iodo- and 2-iodonaphthalenes gave 192 (25%, 22%, <1%), 193 (40%, 36%, 37%) and 194 (<1%, 20%, 15%), respectively. 

The 7r-bonding hypothesis is further supported by calculations of the differences in intrinsic free energy of adsorption, i.e., AGacjs, with the effect of displaced water molecules subtracted. For a series of butyl, phenyl and naphthyl derivatives these were found to be —6-4, —8-9, and —12 4 kcal mole-1, respectively. 

Peroxidases are also active in the oxidation of naphthyl derivatives. In particular, when the substrates are 2-naphthols, the interesting derivatives 1,1 -dinaphthyl-2,2 -diols are formed [23] (Fig. 6.Id). In the presence of suitable substituents blocking the rotation of the naphthyl moieties, chiral binaphthyls can be obtained with enantiomeric enrichment [33, 34]. 

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