Three-Component Reactions of Diazoesters, Aldehydes, and Imines Using a Dual Catalytic System Consisting of a Rhodium(II) Complex and a Lewis Acid
作者:Yasunori Toda、Wakatake Kaku、Makoto Tsuruoka、Sho Shinogaki、Tomoka Abe、Hideaki Kamiya、Ayaka Kikuchi、Kennosuke Itoh、Hiroyuki Suga
DOI:10.1021/acs.orglett.8b00865
日期:2018.5.4
A dual catalytic system, dirhodium tetrapivalate/ytterbium(III) triflate, enables the three-component reactions of α-alkyl-α-diazoesters, aromatic aldehydes, and N-benzylidenebenzylamine derivatives to afford the corresponding β-amino alcohols in good yields after hydrolysis of the oxazolidine cycloadducts, whereas no β-amino alcohols are obtained in the absence of ytterbium(III) triflate. A similar
and efficient three-step sequence for the deamination of α-aminoesters is reported. This method is based on the NaBH4-mediated selective reduction of α-diazoesters to α-hydrazonoesters and has been successfully applied to the deamination of several representative α-aminoesters including some l-cysteine ethyl ester derivatives, key intermediates in the synthesis of a series of CysLT1 antagonists.
A new synthesis of α-fluoro-α,β-unsaturated ketones and esters based on organoselenium methodology
作者:Yoshinosuke Usuki、Michio Iwaoka、Shuji Tomoda
DOI:10.1039/c39920001148
日期:——
Fluoroselenenylation of α-diazoketones and α-diazoesters using a phenylselenenyl fluoride equivalent, generated in situ from phenylselenenyl bromide and AgF, followed by oxidation with hydrogen peroxide, provided α-fluoro-α,β-unsaturated ketones and ester, respectively, in moderate yields.