Diisobutyl aluminum

Table 24. Preparation of Ethyl Alkylidenefluoroacetates from Esters Reduced in situ with Diisobutyl-aluminum Hydride [74]...

The alkyl methacrylate monomers were available from various sources. Isobutyl methacrylate (IBMA) (Rohm and Haas) and t-butyl methacrylate (TBMA) (Rohm Tech) may be purified first by distillation from CaH, followed by distillation from trialkyl aluminum reagents as described in detail earlier (20,21). In particular, t-butyl methacrylate (b.pt. 150°C) was successfully purified by distillation, from triethyl aluminum containing small amounts of diisobutyl aluminum hydride. The trialkyl aluminum and dialkyl aluminum hydride reagents were obtained from the Ethyl Corporation as 25 weight percent solutions in hexane. The initiator, -butyllithium, was obtained from the Lithco Division of FMC, and analyzed by the Gilman "double titration" (22). 

AlRg groups. The latter assumption is favored by the experience that incomplete reaction of the silanol groups occurs always with trimethyl-silyl chloride. This is caused by steric hindrance (219, 220). Diisobutyl aluminum groups are at least as bulky as trimethylsilyl groups. Therefore, since one aluminum atom is bound for every silanol group, a smaller ratio than two of alkyl groups to aluminum must prevail. No carbon determinations have been made, unfortunately. 

In a similar way, the grafting-from technique has been applied to the synthesis of poly(chloroethylvinylether) chains by grafted PCL segments, i.e., po-ly(CEVE-g-CL) graft copolymers. Purposely cationically prepared PCEVE were partially modified by the introduction of 5-10% hydroxyl groups [79]. An equimolar reaction of the pendant hydroxyl functions with HAI/BU2 provided diisobutyl aluminum monoalkoxides dispersed along the polyether backbone. 

Reduction of sulfones to sulfides has been accomplished by lithium aluminum hydride [687], diisobutyl aluminum hydride [659] and sometimes by zinc dust in acetic acid [657]. Diisobutyl aliuninum hydride (Dibal-H) was found to be superior to both lithium alumimun hydride and zinc. At least 2.2 mol of the hydride were necessary for the reduction carried out in mineral oil at room... 

Hexyne, reaction with diisobutyl aluminum hydride, 66, 63 Higher order cuprates, 66, 57... 

The enantioselective synthesis of a somewhat more complex renin inhibitor starts with the reduction of the ester group in the chiral amino-ester (19-1) by means of diisobutyl aluminum hydride in the cold. The aldehyde product (19-2) is then reacted with prior isolation with the ylide from phosphonium salt (19-3) and a strong base... 

Imines, reduction by diIsobutyl aluminum hydride, 66, 189 INDOLE, 4-NITR0-, 65. 146... 

Lithium r-butylUs(2-Diethylpropyl)aluminate, t.i[(/-C4H9) ,Al(/-C4H/>)H] (1). Mol. wt. 206.26. The lithium trialkylaluminate is prepared by reaction of diisobutyl-aluminum hydride with r-hutyllithium. Related hydrides can be prepared with n-butyllithium and. wc-butyllithium. 

Acylthiazolidine-2-thiones (593), easily prepared from carboxylic acids and thiazolidine-2-thione, can be reduced to the corresponding aldehydes with diisobutyl-aluminum hydride in toluene at -78 to -40 °C in 70-90% yield or with lithium tri-f-butoxyaluminum hydride in THF at -20 to 0 °C in 80-90% yield (Scheme 130) (79BCJ555). The formation of the aluminum-containing six-membered chelate (594) in this reaction process is probable and is supported by the fact that no decrease in yield is observed on changing the mole ratio of DIBAL from 1.2 to 2.1 equivalents. 

Lithium aluminum hydride-Hexa-methylphosphoric triamide, 159 Methoxyamine, 177 Titanium(III) chloride-Diisobutyl-aluminum hydride, 303 Trimethylsilyl chlorochromate, 327 From vinylsilanes m-Chloroperbenzoic acid, 76 Miscellaneous methods to prepare ketones... 

Tin(II) chloride-Aluminum, 299 Titanium(IV) chloride-Diethyl-aluminum chloride, 309 Titanium(III) chloride-Diisobutyl-aluminum hydride, 303 Titanium(IV) chloride-Lithium aluminum hydride, 310... 

Our contribution to this area is also included in Scheme 10. The relatively hindered lactone of C-9 alkyl analogues of artemisinin are selectively and efficiently reduced with diisobutyl aluminum hydride (DIBALH) to the P-lactols 141, for example. From the prior workers, the configuration at the C-10 center of... 

Diphenyl ditellurium reacted in tetrahydrofuran with diisobutyl aluminum hydride at 20° to give phenyltelluro diisobutyl aluminum6 (p. 185). 

Disubstituted 4/f-tellurins were obtained by reduction of 4-oxo-4/f-tellurins with diisobutyl aluminum hydride in tetrahydrofuran at 0o1. 

The reduction of 7-methoxy-4-oxo-4//-l-benzotellurins by diisobutyl aluminum hydride produced 4/7-1-benzotellurins2. 

Diisobutyl aluminum hydride reduced 7-methoxy-4-oxo-2-phenyl-4//-l-benzotellurin to the corresponding benzotellurinium salt1. 

Methoxy-2-phenyl-l-benzotellurinium Perchlorate1 1.81 g (5.0 mmol) of 7-methoxy-2-phenyl-4-oxo-4H-1 -benzotellurin are dissolved in 20 ml] of dry tetrahydrofuran, the solution is cooled to — 78°, and 5.5 ml] of a 20% solution of diisobutyl aluminum hydride in hexane are added dropwise via a syringe. The resultant mixture is then slowly warmed to 20°, 20 m/] of a 1.0 molar sodium hydroxide solution are added, the mixture is stirred at 20° for 1 h, and is then poured into 100 ml] of diethyl ether. The organic phase is washed with brine, dried with anhydrous sodium sulfate, filtered, and concentrated. The residue is dissolved in 25 ml] of acetic acid, 2 ml] of 70% perchloric acid are added, and the solution is allowed to cool. The resultant red precipitate is filtered off, washed with several portions of diethyl ether, and air-dried yield 1.13 g (50%) m.p. 150° (dec). 

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