Lithium, 2- 1-naphthyl

Chiral imines derived from 1-phenylethanone and (I. Sj-exo-l, 7,7-trimethyIbicyclo-[2.2.1]heptan-2-amine [(S)-isobornylamine], (.S>1-phenylethanamine or (R)-l-(1-naphthyl) ethanamine are transformed into the corresponding (vinylamino)dichloroboranes (e.g., 3) by treatment with trichloroborane and triethylamine in dichloromethane. Reaction of the chiral boron azaenolates with aromatic aldehydes at 25 "C, and subsequent acidic hydrolysis, furnishes aldol adducts with enantiomeric excesses in the range of 2.5 to 47.7%. Significantly lower asymmetric inductions are obtained from additions of the corresponding lithium and magnesium azaenolates. Best results arc achieved using (.S )-isobornylamine as the chiral auxiliary 3. 

More recently, 4-/m-hutyl- and 4-isopropyl-substituted 4,5-dihydrooxazoles were found to be superior to the original 4-methoxymethyl-5-phenyloxazolines9. Thus, addition of butyl-lithium to 2-(1 - or 2-naphthyl)-substituted 4-ter/-butyl-4,5-dihydrooxazole followed by addition of iodomethane gave adducts in 99 1 and 98.5 1.5 diastereoselection, respectively. The 4-isopropyl analog was less diastereoselective, although the diastereoselection was superior to that of the original 4,5-dihydro-4-methoxymethyl-5-phenyloxazole. 

Benzodiazepin-2-ones are converted efficiently into the 3-amino derivatives by reaction with triisopropylbenzenesulfonyl (trisyl) azide followed by reduction <96TL6685>. Imines from these amines undergo thermal or lithium catalysed cycloaddition to dipolarophiles to yield 3-spiro-pyrrolidine derivatives <96T13455>. Thus, treatment of the imine 50 (R = naphthyl) with LiBr/DBU in the presence of methyl acrylate affords 51 in high yield. 

Tri-(l-naphthyl)phosphine is cleaved by alkali metals in THF solution. " Reaction with sodium gives the naphthalene radical-ion, with lithium the perylene radical-ion, and with potassium the radical-ion (22). Hydrocarbon radical-ion formation was thought to occur via naphthalene derived from the metal naphthalenide. E.s.r. spectra of further examples of phosphorus-substituted picrylhydrazyl radicals have been reported. ... 

Tetrahydro-l-naphthyl hydroperoxide See 1,2,3,4-Tetrahydro-l-naphthyl hydroperoxide Lithium tetrahydroaluminate... 

While it is important for all ester substrates that lithium hexamethyldisilazide be added before warming in order to avoid yield loss, the addition of lithium ethoxide (LiOEt) Is specific for the naphthyl ester and is not generally necessary (see Discussion). Thus for other esters the ethanol can be omitted in this step and the amount of butyllithium can be reduced to 0.20 mol. 

Various substituted phenyl and 2-naphthyl groups were introduced to the / -position of isopropyl ester 78 with enantioselectivities ranging from 93% to 97% ee in high yields in the reactions with lithium arylborates (Scheme 34).110... 

Diastereoselective 1,4- and 1,6-addition reactions of lithium amides to chiral naph-thyloxazolines were used by Shimano and Meyers108-110 for the synthesis of novel amino acids. For example, treatment of (S )-2-(l-naphthyl)-4-t-butyloxazoline with lithi-ated l,4-dioxa-8-azaspiro[4.5]decane and iodomethane provided the diastereomerically pure 1,4-addition product with excellent yield cleavage of the heterocyclic rings then gave the desired /3-amino acid (>99% ee/ds equation 32)108,109. In contrast to this, most acyclic lithium amides reacted with these oxazolines under 1,6-addition the products were transformed smoothly to 5-amino acid derivatives (equation 33)110. 

Optimization of the reaction conditions was undertaken in order to find the best Sn2 /Sn2 ratio and the best substrate conversion. Initial formation of a lithium carbamate salt of 1 on treatment with MeLi, followed by treatment with a stoichiometric amount of MeGu in Et20 at 0 °G, produced clean Sn2 selectivity and isolation of the desired alkene in 75% yield. A variety of chiral carbamates 1 were investigated, the substrate with R = 1-naphthyl and X = OMe being chosen as the candidate for further studies. It is noteworthy that substrates in which X = H gave... 

Similarly, lithium aluminum hydride gives different products. / -Naphthyl p-toluenesulfonate affords p-thiocresol and ) -naphthol, and phenyl meth-anesulfonate gives methyl mercaptan and phenol. On the other hand, propyl p-toluenesulfonate yields />-toluenesulfonic acid and propane, and cetyl meth-anesulfonate and cetyl p-toluenesulfonate give hexadecane in 92% and 96% yields, respectively [680]. 

Miscellaneous The treatment of allyl 1-bromo-2-naphthyl ether 43 with f-BuLi affords benzyl alcohol 44 via a sequential reaction consisting of bromine-lithium exchange, and anion translocation, followed by a [1,2]-Wittig rearrangement (equation 23). ... 

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. 

The reduction of methyl 6-methoxy-2-naphthyl acetate with lithium aluminium hydride in refluxing ether gives 2-(6-methoxy-2-naphthyl)ethanol, which by treatment with PBr3 in refluxing benzene is converted into 2-(6-methoxy-2-naphthyl)ethyl bromide. Further reaction with KCN in refluxing ethanol-water affords 3-(6-methoxy-2-naphthyl) propionitrile, which is finally treated with methylmagnesium iodide in refluxing ethanol. 

Amino-4-methoxy-l-methoxymethylnaphthalene 120, obtained from the chloromethyl derivative 111, is transformed into azide 121. The latter undergoes photolytic heterocyclization to the labile 5-methoxyben-zo[cd]indole 117 which, on reduction by lithium aluminium hydride followed by acetylation, is converted into the stable l-acetyI-5-methoxy-l, 2-dihydrobenzo[o/]indole 119 (R = OMe) [71JCS(C)721]. The reduction of methyl or phenyl 8-nitro-1 -naphthyl ketones by hydrogen and platinum dioxide or by iron in acetic acid leads to a mixture of products (59M634). 

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. 

Conversely, were nucleophilic attack of the alkoxide ion to occur at the carbonyl group of 31, then the species formed (35) should undergo Brook rearrangement to 36 with retention of configuration at silicon (Path A). Reduction of 36 with lithium aluminium hydride would then produce (S)-(—)-l-naphthyl phenyl methyl silane (37). 

---