T-BuOLi

In 2004, Bolm et al. reported the use of chiral iridium complexes with chelating phosphinyl-imidazolylidene ligands in asymmetric hydrogenation of functionalized and simple alkenes with up to 89% ee [17]. These complexes were synthesized from the planar chiral [2.2]paracyclophane-based imida-zolium salts 74a-c with an imidazolylidenyl and a diphenylphosphino substituent in pseudo ortho positions of the [2.2]paracyclophane (Scheme 48). Treatment of 74a-c with t-BuOLi or t-BuOK in THF and subsequent reaction of the in situ formed carbenes with [Ir(cod)Cl]2 followed by anion exchange with NaBARF afforded complexes (Rp)-75a-c in 54-91% yield. The chela-... 

The unimeric model of living PMMA ligated by t-BuOLi was studied by NMR. It was involved in an equilibrium between mixed tetramers" . The complexation rate increased with the reactivity of the complexes. For instance, the [(MiBLi)3 (f-BuOLi)] complex was formed instantaneously, in contrast to the less reactive [(MiBLi)-(f-BuOLi)3] complex... 

A range of other base-solvent combinations were applied with various sulfones. Judka and Makosza have used t-BuOK, t-BuOLi and EtONa in THF or DMF. Reactions of ethyl (benzothiazol-2-yl-sulfonyl)acetate [108] with carbonyl compounds were conveniently carried out using DBU as a base in DCM at reflux (2 molar excess of the sulfone was used). Reaction of methyl tert-butyltetrazolyl sulfones [109] was executed by CS2CO3 in THF-DMF at reflux. 

Treatment with hydrazine to give the hydrazone, and then CuBr2/t-BuOLi, generated the gem-dibromide." Oximes gives gem-dichlorides upon treatment with chlorine and BF3 OEt2, and then HCl." Some dithianes can be converted to gem-difluorides with a mixture of fluorine and iodine in acetonitrile." " Oximes give gem-difluorides with NO BF and pyridinium polyhydrogen fluoride." ... 

Davis and coworkers carried out a Wittig-cyclization sequence with the partially protected 2-deoxyamino sugar 191 using an amino acid based phosphonate. Reaction of 191 with the cesium enolate 192 gave a 53% yield of epimers 193 and 194 (1 1 ratio) in which epimerization of the 2-amino group had taken place. The maimo isomer 194 was then epimerized to the more stable gluco 193 derivative by simple treatment with t-BuOLi in methanol (Scheme 38) [54]. 

Since the data in Tables I to IV show that 100 conversion was attained in as little as 3 minutes, it was decided to determine the actual rates for the butyllithium and lithium t-butoxide in benzene and Hi -furan. A first-order plot is shown in Figure 4 and the first-order rate constants are listed In Table V. Of the two initiators, the t-BuOLi apparently leads to the faster rate in benzene, but both... 

Nickel acetate-2,2 -bipyrklia Biaryls. The bipyridinc aryl halides with LiH-t-BuOLi... 

Note The temperature should not be allowed to rise above —10 °C, since the excess of oxirane may react with t-BuOLi to afford t-BuOCH2CH2OH which is not easy to separate from the desired product. 

H2C=CHCH2NEt2 + BuLi t-BuOK H2C=CHCH(K)NEt2 + t-BuOLi... 

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