Issue 6, 2017

Reversal of the sense of enantioselectivity between 1- and 2-aza[6]helicenes used as chiral inducers of asymmetric autocatalysis

Abstract

Reversal of the sense of enantioselectivity was observed between 1-aza[6]helicene 2 and 2-aza[6]helicene 3 employed as chiral inducers of asymmetric autocatalysis of pyrimidyl alkanol. In the presence of (P)-(+)-1-aza[6]helicene 2, the reaction of pyrimidine-5-carbaldehyde 1 with diisopropylzinc afforded, in conjunction with asymmetric autocatalysis, (S)-pyrimidyl alkanol 4 with high ee. Surprisingly, the reaction in the presence of (P)-(+)-2-aza[6]helicene 3 gave the opposite enantiomer of (R)-alkanol 4 with high ee. In the same manner, (M)-(−)-2 and (M)-(−)-3 afforded (R)- and (S)-alkanol 4, respectively. The sense of enantioselectivity is controlled not only by the helicity of the azahelicene derivatives but also by the position of the nitrogen atom.

Graphical abstract: Reversal of the sense of enantioselectivity between 1- and 2-aza[6]helicenes used as chiral inducers of asymmetric autocatalysis

Supplementary files

Article information

Article type
Communication
Submitted
15 Dec 2016
Accepted
09 Jan 2017
First published
09 Jan 2017
This article is Open Access
Creative Commons BY-NC license

Org. Biomol. Chem., 2017,15, 1321-1324

Reversal of the sense of enantioselectivity between 1- and 2-aza[6]helicenes used as chiral inducers of asymmetric autocatalysis

A. Matsumoto, K. Yonemitsu, H. Ozaki, J. Míšek, I. Starý, I. G. Stará and K. Soai, Org. Biomol. Chem., 2017, 15, 1321 DOI: 10.1039/C6OB02745H

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