Lithium, tris methyl

Lithium 2,6 dimethylphenoxide, from 2,6-dimethylphenol, 46,115 methylation of, to form 2,6,6-tri-methyl 2,4 cyclohexadienone, 46, US... 

Lithium-tri-tert.-butyloxy-hydrido-alanat6 (nur aus Phenylestern) Bis-[4-methyl-piperazino]-alummiumhydrid7... 

Dagegen werden 2-Oxo-3-acyl-l,3-thiazolidine mit Lithium-tri-tert.-butyloxy-hydri-do-aluminat bzw. Bis-[2-methyl-propyl]-aluminiumhydrid selektiv zu Aldehyden reduziert5. 

Natriumboranat/Pyridin > Lithium-tetrakis-[l,2-dihydro-pyridyl-(l)]-aluminat > Natriumboranat/Alkohol > Lithium-tri.-tert.-butyloxy-hydrido-aluminat > Lithiumalanat > Lithium-trimethoxy-hydrido-aluminat > Aluminiumhydrid > Bis-[2-methyl-propyl]-aluminiumhydrid... 

Semmelhack et al. chose CuBr, together with either Red-Al or LiAl(OMe)3H in a 1 2 ratio, to afford presumed hydrido cuprates, albeit of unknown composition [llj. In THF, both the former Na complex and the latter Li complex are heterogeneous (and of differing reactivities), yet each is capable of 1,4-reductions of unsaturated ketones and methyl esters (Eq. 5.4). Commins has used a modified version, prepared from lithium tri-t-butoxy-aluminium hydride and CuBr (in a 3 4.4 ratio), to reduce a 3-substituted-N-acylated pyridine regioselectively at the a-site [12]. 

Esters are also reduced by sodium aluminum hydride (yields 95-97%) [<9<9] and by lithium trimethoxyaluminum hydride (2 mol per mol of the ester) [94] but not by lithium tris tert-butoxy)aluminum hydride [96], Another complex hydride, sodium bis(2-methoxyethoxy)aluminum hydride, reduces esters in benzene or toluene solutions (1.1 -1.2 mol per ester group) at 80° in 15-90 minutes in 66-98% yields [969], Magnesium aluminum hydride (in the form of its tetrakistetrahydrofuranate) reduced methyl benzoate to benzyl alcohol in 58% yield on refluxing for 2 hours in tetrahydrofuran [59]. 

Optimization of the previously reported Mannich-type reaction of trimethyl (pent-2-en-3-yloxy)silane with the sulfone Is derived from phenyl acetaldehyde (Table 5, entry 11) led to the corresponding (3-amino ketone in a good yield with moderate diastereoselectivity (2 mol% Bi(0Tf)3-4H20, yield = 84%, 24v/24v syn/anti = 72 28) (Scheme 8). Reduction of the major diastereoisomer 24v with lithium tri-ferf-butoxyaluminohydride afforded 25 as the only one diastereoisomer. Further cyclization of the latter with NaH afforded 4-benzyl-6-ethyl-5-methyl-l,3-oxazinan-2-one 26. The relative configuration of the six-membered carbamate was established as cis-cis by NMR analysis. 

O-silylierte, -acetylierle oder -benzoylierte 2-Hydroxy-carbonsaure-nitrile erhalt man ohne Katalysator und bei 20° aus aliphatischen und aromatischen Aldehyden sowie aus aliphatischcn und a, /J-ungesat-tigtcn Ketonen in einer einfach durchzufuhrenden Eintopf-Reaktion mit Lithium-cyanid und Chlor-tri-methyl-silan, Acetylchlorid oder Benzoylchlorid in THF6. 

Das nachstehende Beispiel beschreibt als allgemeine Methode die reduktive Demethylie-rung von Alkyl- bzw. Aryl-trimethyl-ammonium-Salzen mit Lithium-tris-[l-methyl-pro-pyl]-boranat (L-Selectride) zu tertiaren Aminen2. 

Fig, 4. Observed proton septet spectra, for hydrogen atoms coupled with 10B in (a) lithium borohydride, (b) trimethylamineborane, and (c) jV-tri(methyl-rf3) borazine. 

Several synthetic methods for the reduction of a-amino esters have also been reported. The reduction of methyl or ethyl esters by diisobutylaluminum hydride (DIBAL-H) at low temperature (—78 °C) has been described as useful for the preparation of a-amino aldehydes. 1118 20 Again, this method suffers from overreduction. Reductive methods involving mild reductive agents have been described. The reduction of phenyl esters 6 21 (readily prepared from the corresponding amino acid 5) with lithium tri-ferf-butoxyaluminum hydride is efficient for the preparation of various Boc-a-amino aldehydes including Na-Boc-7V J-nitroargininal and A7a-Boc-W"-Z-argininal (Scheme 5). 

Oxidation reactions r-Butyl hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 51 m-Chloroperbenzoic acid, 76 Reduction reactions Chlorodiisopinocampheylborane, 72 Diisobutylaluminum hydride-Tin(II) chloride- (S) -1 - [ l-Methyl-2-pyrrolidi-nyljmethylpiperidine, 116 Lithium borohydride, 92 Lithium tri-sec-butylborohydride, 21 B-3-Pinanyl-9-borabicyclo[3.3.1]-nonane, 249... 

Acetyl- and 5-formylisothiazoles are readily available from 5-lithioisothiazoles.71,102 However, 3-methyl-4-nitroisothiazole does not form a lithium derivative,72 and 4-formyl-3-methyl-4-nitro-isothiazole was prepared by reduction of the appropriate acid chloride with lithium tri-Lbutoxyaluminum hydride.140 A 5-formyl-4-hydroxy-isothiazole has been prepared by direct ring synthesis [Eq. (12)].29... 

For the study of the physical and chemical properties of triply unsaturated fatty acids and for the comparison with y-linolenoic acid [6Z,9Z.12Z)-6,9,l2-octadeca-trienoic acid] coworkers of the Unilever Research Centre in Vlaardingen (Netherlands) synthesized some methyl esters of ( ,Z,Z)-trisunsaturated fatty acids 73). For the preparation of the esters of (2E,9Z, 12Z)-2,9,12-octadecatrienoic acid and of (2 ,11Z,14Z)-2,11,14-eicosatrienoic acid (68 a and b) they used the Wittig reaction to introduce the ( )-2-double bond into the starting diunsaturated aldehyde. Reduction of the acid chlorides of (7Z,10Z)-7,10-hexadecadienoie acid and of linolenoic acid (65a and b) with lithium tri-tert-butoxyaluminium hydride affords the corresponding aldehydes 66 a and b which can be olefinated with the stable ylide 67 to methyl ( ,Z,Z)-alkatrienoates 68a, b with a (Z)-2-isomer content of 4.6%73) (Scheme 13). 

A facile, one-pot synthesis of an alkylated tetrahydrofuranone intermediate was applied to the synthesis of a novel hexahydrofuro[3,4-6]furan derivative <83TL2335>. Reaction of methyl acrylate with methyl sodium benzilate in DMSO gave the intermediate 3-oxo ester carbanion, which was alkylated with allyl bromide to yield the tetrahydrofuranone derivative (408). Subsequent hydrolysis and decarboxylation of (408), followed by reduction with lithium tri-r-butoxyaluminum hydride gave compound (409), which with excess iodine and Na2C03 afforded an 85 15 mixture of the epimers (410a) and (410b) in 95% yield (Scheme 38). 

Kalium-bis-[trif]uormethyl]-hydro-lriiluor- E2, 905 Kalium-hydro-tetrafluor-trifluor-methyl- E2, 904 Lithium-tris-[2,2 -diphenyldiylJ- E2, 907 Natrium-pentafluor-phenyl-... 

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