Lithium octyl, reaction

Neither ol the two reactions involved in the conversion of the iodide to the acid is definitely known to involve a free carbanion. The racemiza-tion of the sec-octyl lithium when it is warmed to 0° for twenty minutes before carbonation may be a matter of ionization at the higher temperature, less optical stability of the carbanion at the higher temperature, or both. 

Propargyl alcohol (0.50 mol) is added dropwise over 15 min to a suspension of 1.10 mol of lithium amide in -700 ml of liquid ammonia. Subsequently, 0.40 mol of octyl bromide (short measure) is added over 30 min, directly followed by 350 ml of DMSO (for drying DMSO see ref. 1). The temperature of the reaction mixture rises gradually while salt begins to separate (this may redissolve at a later stage). The ice crust on the outside of the flask is occasionally removed by spraying with acetone. Stirring at 10 to 15 C is continued for an additional hour. 

The Diels-Alder reaction of 3-methoxyfuran with octyl vinyl ketone took place at room temperature in quantitative yield to afford exclusively the endo cycloadduct (27) (81CC221). Reduction of the carbonyl group with lithium tri-r-butoxyaluminum hydride produced a single alcohol (28). Ozonolysis of the double bond followed by Jones oxidation yielded the lactone ester (29). Hydrolysis of the ester and lead tetraacetate oxidation gave the lactone acetate. This was converted by further hydrolysis and Jones oxidation to the bis-lactone (30), a known intermediate in the synthesis of ( )-isoavenaciolide (Scheme 6). 

Another example involves alkylation of the lithium salt of the anthracene anion radical by 2-octyl fluoride (Herbert et al. 1985). The akylation does not occur in dimethylfor-mamide (which strongly solvates Li+), whereas it is facilitated and becomes a quantitative reaction in diethyl ether. Coordination of the type (>CH—F " Li+), which is possible in a slightly basic solvent such as diethyl ether, seems to be the decisive factor in the reaction. 

Generation of enol silyl ethers from acyclic ketone precursors can be accomplished using the same kind of reagents. Depending on the reaction conditions, stereoselective formation of either the ( )- or the (Z)-isomer of the enol silyl ethers has been reported (Scheme 11). An in situ method of generating the enolate anion with lithium dialkylamides in the presence of trimethylchlorosilane leads to enhanced selection for the kinetically preferred enol silyl ether (e.g. 34a). Lithium r-octyl-r-butylamide (LOBA) is... 

In the absence of more acidic hydrocarbons, ethylene serves as both telogen and taxogen. The addition of ethylene to the lithium-carbon bond was previously observed by Ziegler, et al. (16). Those authors also found that ether catalyzes the addition reaction. However only growth products such as hexyl-, octyl-, and decyllithium were formed. 

Isomerization is observed with higher alkyl halides, as in Friedel-Crafts reactions isopropylphosphonic dichloride is stated to be the sole product from n-propyl chloride,190,191 and terf-pentyl chloride undergoes C-C fission, yielding the tert-butyl acid.193 On reduction by lithium tetrahydroaluminate the phosphonic chloride formed from w-butyl chloride gives a primary phosphine that is shown by 31P-nuclear magnetic resonance to consist of n- and sec-butylphosphine in the proportions 5 95 and the product from n-octyl chloride was similarly shown to contain all four position isomers.194... 

A bbreviations PS - photosystem, RC - reaction center, Chl-pro-tein - chlorophyll-protein, PAGE - electrophoresis in polyacrylamide gel, LHC - light-harvesting complex, SDS - sodium dodecyl sulfate, LiDS - lithium dodecyl sulfate, OGP - octyl- -D-gluco-pyranoside, kDa — kilodalton, P595 - fluorescence with a maximum at 695 nm, Pheo - pheophytin FP - free pigment. 

Results and Discussion. Figure 1 shows an example separation of Chlamydomonas chlorophyll-protein complexes solubilized with a mixture of octyl glucoside, decyl maltoside, and lithium dodecyl sulfate. The left hand panel shows the unstained green band pattern, while the right hand panel shows intrinsic room temperature chlorophyll fluorescence with excitation at 365 nm. This technique allows for the rapid assignment of antenna complexes, which fluoresce brightly, and reaction center complexes which are non-fluorescent or only weakly fluorescent at room temperature. 

The same group reported an extension of the direct alkylation of (benz)oxazoles with various alkyl bromides and chlorides by using the stronger base lithium tert-butoxide (Scheme 19.23) [38]. 5-Aryloxazoles containing electronically diverse substituents such as CFj and OMe were also alkylated successfully. Various linear alkyl chains were introduced, such as phenylpropyl, citronellyl, or octyl, affording interesting lipophilic molecules. The optimized reaction conditions failed to apply to benzothiazoles, and the authors had to turn their attention to nickel catalysis to achieve the corresponding alkylation (Section 19.2.3). Experiments were run to understand the reaction mechanism that presumably involves Sj 2-type oxidative addition of the alkyl halide to palladium(O) followed by transmetallation by the in situ-lithiated (benz)oxazole (Scheme 19.24). 

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