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Synfacts 2011(5): 0493-0493  
DOI: 10.1055/s-0030-1259795
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart ˙ New York

A Well-Oiled Stereodynamic Probe

Contributor(s):Timothy M. Swager, Olesya Haze
D. P. Iwaniuk, C. Wolf*
Georgetown University, Washington, USA
A Stereodynamic Probe Providing a Chiroptical Response to Substrate-Controlled Induction of an Axially Chiral Arylacetylene Framework
J. Am. Chem. Soc.  2011,  133:  2414-2417  
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Publication History

Publication Date:
15 April 2011 (online)

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Key words

axial chirality - stereodynamic probe - chiroptical response - induced circular dichroism

Significance

A series of Sonogashira cross-­coupling reactions is employed in the synthesis of the aryl-acetylene stereodynamic probe 1, which was obtained in 62% overall yield. While 1 is achiral, condensation with chiral di- or monoamines produces axially chiral diimines (e.g. 2). Because of the unhindered rotation in 1 (blue arrows) the central-to-axial chirality induction is essentially ‘frictionless’.

Comment

Extraordinary chirality amplification and strong Cotton effects were observed, and were used for in situ induced circular dichroism (ICD) analysis of a variety of chiral amines. CD amplitudes showed linear dependency on % ee, and enantiomeric excess was determined within 4% of the actual values for trans-1,2-diaminocyclohexane, and within 5.5% for the isopinocampheyl­amine.

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