Asymmetric reduction of aliphatic ketones and acyl silanes using chiral anti-pentane-2,4-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid

Aliphatic ketones were reduced to the corresponding secondary alcohols by using anti-1,3-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid (DNBSA) in benzene at reflux. Addition of 1-octanethiol in that media improved the efficiency of the reduction. Asymmetric reduction of aliphatic ketones was performed by using chiral anti-pentane-2,4-diol, and highly asymmetric induction (up to >99% ee) was observed in the reduction of tert-alkyl ketones. Asymmetric reduction of acyl silanes using chiral anti-pentane-2,4-diol and DNBSA proceeded efficiently in the absence of octanethiol and the corresponding α-silyl alcohols were obtained in high yields with high ees.     

Curved Phenine Normal Vectors: Geometric Measures of Geodesic Phenine Frameworks

A vector was introduced to quantitatively describe the pyramidalization of 1,3,5‐trisubstituted benzene (phenine). The vector, named curved phenine normal vector (CPNV), defined the direction of pyramidalization of the trigonal phenine panel and quantified the degree of pyramidalization. The relative orientation of the two CPNVs further defined a dihedral angle, which quantified interphenine torsions. The CPNV analysis visually showed the geometric features of nanometer‐sized molecules by revealing the important role of torsions. Biased electrostatic potentials were also correlated with CPNV pyramidalizations.