2-Allyl-l-naphthols

Naphthofurans have been synthesized from the corresponding naphthols thus 2-methoxy-3-allylnaphthalene (from allyl bromide and 3-lithio-2-methoxynaphthalene) gives 2-methyl-2,3-dihydronaphtho-[2,3-6]furans,435 and l-allyl-2-naphthol gives (with pyridine hydrochloride) 2-methyl-2,3-dihydronaphtho[2, l-6]furan.438... 

MethylT2,l-f)]naphthofurane (4) was obtained by this method from l-allyl-2-naphthol (3). 

Transition-metal-catalyzed processes often work nicely for the aromatic Claisen rearrangement. Mechanistic aspects might be different from those under usual thermal conditions. Platinum complexes catalyzed the reaction of allyl 2-naphthyl ether 41 to afford l-allyl-2-naphthol 42 regioselectively in excellent yield [40]. Molybdenum hexacarbonyl also catalyzed the one-pot conversion of allyl aryl ethers to coumaran derivatives such as 43 from 17 [41]. 

Bis(oxazoline) ligands have also been employed in the catalytic enantioselective aza-Claisen rearrangement of allylic imidates, " chirality recognition in the determination of the ee of l,l -bi-2-naphthol, " and the enantioselective formation of double and triple helicates. 

V,A,iV, Ai -Tetraethyl-l,l -bi-2-naphthol-3,3 -dicarboxamide (20) has been shown by KatsuTi and coworkers to be quite effective as a stoichiometric additive in the cyclopropanation of allylic alcohols (equation 89) . The best enantioselectivities were obtained with aryl-substituted allylic alcohols however, 6 equivalents of diethylzme were needed. 

Optically pure aluminum reagent (R)-151 was synthesized from 1 equiv. each of (R)-(-i-)-3,3 -bis(triarylsilyl)-l,l -bi-2-naphthol and MejAl [196], on the basis of the structure of MAPH [197]. Chiral (R)-151 is an excellent promoter of the asymmetric Claisen rearrangement of allyl vinyl ethers 152 or 153 which have bulky substituents such as trialkylsilyl- or trialkylgermanium groups, but is totally ineffective for sterically less hindered substrates (Scheme 6.152). 

An effective chiral catalyst for asymmetric allylation of aldehydes or ketones is the complex formed between the axially chiral l,l -bi-2-naphthol (BINOL) 164 and a titanium(IV) salt." Addition of allyltributylstannane to an aldehyde using this Lewis acid gives the product homoallylic alcohol with high optical purity. For example, allylation of iso-butyraldehyde gave the alcohol 165 as a 98 2 ratio of enantiomers (1.155). Use of (5)-BINOL gave the other enantiomer of the product. 

Cyctohexadienones. The acid-catalysed rearrangement of the l-allyl-l-methyl-2-naphthalenone (57 R = H) in acetic acid, diethyl ether, or acetic anhydride gave 4-allyl-l-methyl-2-naphthol or its acetate as the sole product. Deuterium labelling... 

As mentioned earlier, much less efficient methods are available for allylation of imines than for allylation of aldehydes. Accordingly, the pincer-complex-catalyzed allylation of imines attracted considerable attention. In particular, the asymmetric version of this process is very important, as it grants access to chiral homoal-lylamines. The Szabo group [81j,l] developed a,Q ,a, a -tetraaryl-l,3-dioxolan-4,5-dimethanol (TADDOL-), l,l -bi-2-naphthol (BINOL-) and bisphenantrole-based chiral pincer complexes to achieve asymmetric allylation reactions (Scheme 6.28). 

Consecutive condensations of 2-naphthol, allylamine, and dibromomethane comprised another route to naphthalene-condensed 1,3-oxazines. A preheated mixture of allylamine and dibromomethane was reacted with 2-naphthol 152 to yield the aminophenol intermediate 520, which was cyclized with the salt formed in the reaction of dibromomethane and diethylamine to give 3-allyl-3,4-dihydro-2//-naphth[l,2-< ][l,3]oxazine 521 on further reaction (Scheme 98) <2004SC2253>. 

Sol 4. (a) Allyl ether of 2-naphthol (I) on heating undergoes Claisen rearrangement to give l-aIlylnaphthalen-2-ol (II) and 3-allylnaphthalen-2-ol (HI). Reaction favors the formation of II as the aromaticity in the intermediate enone is lost only in one ring. However, in the formation of III aromaticity in the intermediate enone is lost in both the rings. 

H,40) 2 Propionyloxy diphenyl 4II623. [4 Bm l phenyl) aoetat 6. 676. Benzhydiylaoetat 6. 680,1 6. II 4. O Phenyl benzylalkohol acetat 6, 682. l Allyl naphthol-(2) acetat 6 I 328. 3 Acetoxy. 2-isopiopenyl naphthalin 61328. t M AOxy-phenoxy) Styrol 6. 772. a t Methoxy pbenoxyj etyrel 6. 815. 4 Oxy 2 metboxy-stilben 6 14. 4 0xv 3 inethoxy-8tilben 6 II967. 9.lO Dioxy 2 methyM.4 dihydro-anthracen 6 0 993. 

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... 

An unusual domino process was observed by Biehl and coworkers [69] in the reaction of 2-bromo-l-naphthol 4-196 with arylacetonitriles in the presence of LDA or LiTMP by employing 3-thienylacetonitrile 4-197, the tetracyclic compound 4-200 was obtained in 57% yield (Scheme 4.43). The reaction probably includes the formation of an aryne and a ketenimine which undergo [2+2] cycloaddition to give 4-198, followed by rearrangement and allylic addition to the intermediately formed aryl cyano compound 4-199. 

Substituted-l-naphthols are synthetic phenolic compounds with dual inhibitory activities. The most active compound, 2-allyl-l-naphthol, is a very potent 5-LOX inhibitor with an IC50 value in nanomolar range and also has moderate COX enzyme inhibition activity. The compound also possesses excellent topical anti-inflammatory potency in the mouse ear edema model... 

Transformations involving chiral catalysts most efficiently lead to optically active products. The degree of enantioselectivity rather than the efficiency of the catalytic cycle has up to now been in the center of interest. Compared to hydrogenations, catalytic oxidations or C-C bond formations are much more complex processes and still under development. In the case of catalytic additions of dialkyl zinc compounds[l], allylstan-nanes [2], allyl silanes [3], and silyl enolethers [4] to aldehydes, the degree of asymmetric induction is less of a problem than the turnover number and substrate tolerance. Chiral Lewis acids for the enantioselective Mukaiyama reaction have been known for some time [4a - 4c], and recently the binaphthol-titanium complexes 1 [2c - 2e, 2jl and 2 [2b, 2i] have been found to catalyze the addition of allyl stannanes to aldehydes quite efficiently. It has been reported recently that a more active catalyst results upon addition of Me SiSfi-Pr) [2k] or Et2BS( -Pr) [21, 2m] to bi-naphthol-Ti(IV) preparations. 

Irradiation of 2,3,3-triphenyl-l-cyclopropenylcarboxaldehyde (52) led to a naphthol derivative (55) in benzene or to an allylic ester (56) in methanol. 

The oxidation of 2-aUyl-l-naphthols leads to 4-allyl-1,2-naphthoquinones (4 examples, 65-73%) as a result of hydroxylation followed by oxy-Cope rearrangement. ... 

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