Enantioselective protonation of samarium enolates by a C2-symmetric chiral diol
摘要:
High enantioselectivity (up to 97%ee) have been achieved in the protonation of samarium enolates which were generated by SmI2-mediated cross-coupling reaction between unsymmtrical dialkylketene and allyl iodide, using a C-2-symmetric chiral diol as a proton source. The stereochemistry of enolate formation and of the enantioselective protonation is discussed.
Asymmetric Synthesis of Ketones by SmI<sub>2</sub>-Mediated Allylation or Benzylation of Ketenes Followed by Enantioselective Protonation
作者:Seiji Takeuchi、Norikazu Miyoshi、Yoshiaki Ohgo
DOI:10.1246/cl.1992.551
日期:1992.4
SmI2-mediated allylation or benzylation of alkylarylketenes followed by enantioselective protonation with α,α′-di[(S)-2-hydroxy-2-phenylethyl]-o-xylenedioxide gave the corresponding ketones in 61–91%ee.
High enantioselectivity (up to 97%ee) have been achieved in the protonation of samarium enolates which were generated by SmI2-mediated cross-coupling reaction between unsymmtrical dialkylketene and allyl iodide, using a C-2-symmetric chiral diol as a proton source. The stereochemistry of enolate formation and of the enantioselective protonation is discussed.
Catalytic enantioselective protonation of samarium enolates by a C2-symmetric chiral diol
Relatively high enantioselectivity (up to 93% ee) has been achieved in the catalyticprotonation of samarium enolates by the use of a C2-symmetric homochiral diol as the catalyst and trityl alcohol as an achiral proton source for regeneration of the catalyst.