Pentyl lithium

Several reagents reduce aldehydes preferentially to ketones in mixtures of both. Very high selectivity was found in reductions using dehydrated aluminum oxide soaked with isopropyl alcohol and especially diisopropylcarbinol [755], or silica gel and tributylstamane [756]. The best selectivity was achieved with lithium trialkoxyalumimm hydrides at —78°. In the system hexanal/ cyclohexanone the ratio of primary to secondary alcohol was 87 13 at 0° and 91.5 8.5 at —78° with lithium tris(/er/-butoxy)aluminum hydride [752], and 93.6 6.4 at 0° and 99.6 0.4 at —78° with lithium tris(3-ethyl-3-pentyl-oxy)aluminum hydride [752],... 

The third synthetic route reported by Husson and co-workers 140) is as follows Amino nitrile 472 obtained from the ketal (471) was converted to the 2,6-dialkylpiperidine (473) by catalytic hydrogenation followed by alkylation with lithium diisopropylamide and pentyl bromide. Refluxing a solution of 473 in methanol containing hydrochloric acid led to the formation of 9-benzyladaline (475) in 90% yield. Debenzylation of 475 gave d/-adaline (107) in nearly quantitative yield (Scheme 59) 140). 

Die analoge Reaktion von Thiocarbonsaure-amiden, z. B. Thiobenzoesaure-morpholid, mit Butyl-lithium und Reduktion des nicht isolierten Zwischenproduktes mit Lithium-alanat ergibt Amine z.B. 4-(1-Phenyl-pentyl)-morpholin ( 90%) und analog 4-[I-(4-Melhoxy-phenyl) -pentyl -morpholin (59%)1 ... 

Bei der nachstehenden Reaktionsfolge zur C-Alkylierung eines sekundaren Methylamins wird iiber N-Lithiierung in mehreren Schritten ein Lithium-dithiocarbamat hergestellt, das noch im Reaktionsgemisch sauer zu Butyl-pentyl-amin (85%) hydrolysiert wird2. 

Tetrasilapentanes 4, R = Pr or neo-pentyl, were synthesized by reductive coupling of the linear 1,5-dichloro-l,2,4,5-tetrasilapentane with lithium biphenyl in 77-87% yields <2002EJI1772>. 

The more reactive ft -carbon atom of ketone a,/ -dianions can be regiospecifically coupled with alkyl halides to give first lithium enolates, which are then trapped by more reactive carbon electrophiles such as allylic halides. The first example shown in Table 8 deals with the sequential /1-alkylation and ce-allylation of a ketone a,/1-dianion1 13. Thus, the dianion underwent regioselective alkylation at the ft carbon with //-pentyl bromide and then allylation with allyl bromide at the a carbon. When an excess of allyl bromide is reacted with the a, ft -dianion, the diallylated product is obtained in a good yield, whereas a threefold excess of pentyl bromide only resulted in the formation of the ft-alkylation product. Similar consecutive alkyl/allyl-type reactions are also possible for ketone a,5-dianions14. 

Cyclic non-conjugated (139 and 140) or conjugated (141 and 142) dienamines may be obtained by Birch reduction of the corresponding aromatic amine552,553. The preferred conditions involve the use of lithium and t-pentyl alcohol rather than ethanol, since the latter tends to give a considerably higher proportion of the further reduced tetrahydro derivative554. 

Boranat Lithium[(2S)-(3-Methyl-2-butenyl)-pentyl]- E21d, 4414 [R2B-OR + LiAl(OR)H3]... 

Only the most electropositive metals, the alkali metals and alkaline-earths, form hydrosulphides. LiSH is particularly unstable, being very sensitive to hydrolysis and oxidation, and decomposes at temperatures above about 50°C. It may be prepared in a pure state by the action of HjS on lithium n-pentyl oxide in ether solution. Its structure is of the zinc-blende type and similar to that of UNH2, but there is considerable distortion of the tetrahedral coordination groups ... 

CpTiCl3 reacts with lithium[3-(o-methoxy-phenyl)pentyl cyclopentadienide] to give the bis-Cp complex where the Cp ligands support methoxo functionalities (Scheme 471).815... 

In the 1950s, it was reported that the reaction of cyclopropane with lithium aluminum hydride gave tripropylaluminum. However, this result was not verified. The reaction of cyclopropane in the vapor phase with diborane to monoalkylcyclopropanes was shown to be fairly regioselective, the products being derived from addition of the hydride to the most-substituted carbon atom, and the boron to the least-substituted carbon atom. With butyl-, pentyl- and octylcyclopropanes after oxidative workup the linear primary alcohols 3 were obtained as the major products together with small quantities of the 2-methyl derivatives 4. 

Benzothiazol wird durch die Behandlung mit Butyl-lithium und anschlieBend mit Dichlor-diisopropylamino-boran in maBigen Ausbeuten in 3-(1-Butyl-pentyl)-2-(diisopropylamino)-... 

Lithium (2.V)-(3-lVlcthylbut-2-yl)pentyl borohydride Single Procedure1 8 ... 

The reaction can be effected at low temperature or at the boiling point of the amine. Methylamine or a lower homolog, ethylenediamine,58 or an alkyl-aniline56 is usually used. They often act simultaneously as proton donors, but in other cases ammonium salts must be added after termination of the reaction. In reductions of abietic acid derivatives it was shown that reaction of lithium in ethylamine is milder than in presence of tert-pentyl alcohol.59 A review of these reactions is given by Birch and Smith.60... 

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... 

Methoxyphenyl n-pentyl ketone was formed in 85% yield by the addition of a mixture of anisole and caproic anhydride in dichloromethane to a suspension of lithium perchlorate (1 mole) and a small proportion of antimony pentachloride (allowed first to stir together for 1 hour) in dichloromethane, followed by refluxing for 30 mins., and work-up by quenching with aqueous sodium bicarbonate (ref. 124). 

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