Trityl samarium

Reductive coupling of carbonyls to alkenes Titanium(IV) chloride-Zinc, 310 of carbonyls to pinacols Titanium(III) chloride, 302 Titanium(IV) chloride-Zinc, 310 of other substrates Samarium(II) iodide, 270 Reductive cyclization 2-(Phenylseleno)acrylonitrile, 244 Tributylgermane, 313 Tributyltin hydride, 316 Triphenyltin hydride, 335 Trityl perchlorate, 339 Reductive hydrolysis (see Hydrolysis) Reductive silylation Chlorotrimethylsilane-Zinc, 82... 

Norephedrine, 200 Organoaluminum reagents, 202 Organotitanium reagents, 213 9-(Phenylseleno)-9-borabicyclo-[3.3.1]nonane, 245 Tin(II) chloride, 298 Titanium(IV) chloride, 304 Trityllithium, 338 Trityl perchlorate, 339 Zinc chloride, 349 By other reactions Chloromethyl ethyl ether, 75 Dibutyltin oxide, 95 Samarium(II) iodide, 270 Tributyltin hydride, 316 Hydroxy amides a-Hydroxy amides... 

A C2-symmetric homochiral diol 13 (DHPEX) is a chiral proton source developed by Takeuchi et al., for samarium enolates which are readily prepared by Sml2-mediated allylation of ketenes [25,26]. In the stoichiometric reaction using DHPEX 13, they found that -45 C was the best reaction temperature for the enantioface discrimination, e.g., when methyl (1-methyl-l-phenylethyl)ketene 55 was used as a substrate, the product exhibited 95% ee [27]. The catalytic reaction was carried out using trityl alcohol as an achiral proton source which was added to a mixture of in situ generated samarium enolate 56 and DHPEX 13 (0.15 equiv) slowly so as not to exceed the ratio of the achiral proton source to DHPEX 13 of more than 0.7. The highest ee (93% ee) of product 57 was gained when the achiral proton source was added over a period of 26 h (Scheme 8) [27]. 

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