Tetrabutylammonium iodide-catalyzed oxidative coupling of enamides with sulfonylhydrazides: synthesis of β-keto-sulfones
作者:Yucai Tang、Ye Zhang、Kaifeng Wang、Xiaoqing Li、Xiangsheng Xu、Xiaohua Du
DOI:10.1039/c5ob00742a
日期:——
A facile syntheticroutetowards pharmaceutically interesting β-keto-sulfone derivatives by tetrabutylammonium iodide (TBAI)/tert-butyl hydroperoxide (TBHP) mediated oxidative coupling of readily prepared enamides with economical sulfonylhydrazides is described. The corresponding β-keto-sulfone compounds were obtained in moderate to good yields. The present method is metal-free and base-free and shows
A new family of ferrocenylphosphane ligands has been prepared. Their flexible synthesis allows many structural modifications. The asymmetric induction of these ligands was examined in the hydrogenation of functionalized C=C, C=O, and C=N bonds. The enantioselectivity of the reaction was strongly dependent on the substituent R at the position alpha to the ferrocene moiety. In many cases, both enantiomeric
Practical Enantioselective Hydrogenation of α-Aryl- and α-Carboxyamidoethylenes by Rhodium(I)-{1,2-Bis[(<i>o</i>-<i>tert</i>-butoxyphenyl)(phenyl)phosphino]ethane}
作者:Barbara Mohar、Michel Stephan
DOI:10.1002/adsc.201200780
日期:——
The rhodium(I)-1,2-bis[(o-tert-butoxyphenyl)(phenyl)phosphino]ethane} [Rh(I)-(t-Bu-SMS-Phos)] catalyst system displayed prime efficiency in the hydrogenation of large series of α-amidostyrenes and α-amidoacrylates. Up to >99.9% enantiomeric excesses coupled with very high reaction rates were attained operating routinely under 1–10 bar of hydrogen at 22 °C in methanol. Examples include industrial substrates
Catechol-Based Phosphoramidites: A New Class of Chiral Ligands for Rhodium-Catalyzed Asymmetric Hydrogenations
作者:Rob Hoen、Michel van den Berg、Heiko Bernsmann、Adriaan J. Minnaard、Johannes G. de Vries、Ben L. Feringa
DOI:10.1021/ol049726g
日期:2004.4.1
[reaction: see text] The synthesis and application of a new class of catechol-based phosphoramidites is described. Ees up to 99% were obtained in the rhodium-catalyzedasymmetrichydrogenation of dehydroamino acids and enamides.
A new family of readily available, recoverable and soluble polymer-monophosphite ligands were prepared and successfully used in the Rh-catalyzed asymmetric hydrogenation of enamides and β-dehydroamino acid esters, in which up to 99 and 99.9% ee were obtained, respectively.