<i>trans</i>-1,2-Diaminocyclopentane-Based Catalyst for the Asymmetric Addition of Alkyl-, Aryl-, and Vinyl Groups to Ketones
作者:Patrick J. Walsh、Cecilia Anaya de Parrodi
DOI:10.1055/s-2004-832826
日期:——
The catalytic asymmetric addition of ethyl-, phenyl-, and 1-hexenyl groups to ketones is reported. The new catalyst, generated from titanium isopropoxide and a bis(sulfonamide) diol ligand based on trans-1,2-diaminocyclopentane, gives good to excellent enantioselectivities with a range of substrates.
A Convenient Method for the Preparation of Inverted <i>tert</i>-Alkyl Carboxylates from Chiral <i>tert</i>-Alcohols by a New Type of Oxidation−Reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone
Oxidation-reduction condensation using in situ-formed alkoxydiphenylphosphines, 2,6-dimethyl-1,4-benzoquinone, and carboxylic acids provided a new and efficient method for the preparation of inverted tert-alkyl carboxylates from various chiral tertiary alcohols.