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Highly Efficient Syntheses of C−N Axially Chiral 1‐(ortho‐hydroxyaryl)uracil using a Chiral Auxiliary and a Chiral Base

Highly Efficient Syntheses of C−N Axially Chiral 1‐(ortho‐hydroxyaryl)uracil using a Chiral... We achieved a highly diastereoselective synthesis of 1‐aryl‐6‐aminouracils, which are C−N atropisomeric compounds, through the combined use of a chiral auxiliary and a chiral base under mild conditions. We found that the (R)‐5‐allyl‐2‐oxabicyclo[3.3.0]oct‐1‐yl group is a good chiral auxiliary that, when combined with quinidine, efficiently affords 1‐aryl‐6‐aminouracils with high diastereoselectivity (up to 98 % ee after isolation). The chiral alcohol moiety in quinidine appears to be crucial for achieving stereoselectivity during cyclization. Furthermore, the chiral auxiliary was easily removed from the product under acidic conditions to provide the atropisomer with high enantiomeric excess (up to 96 % ee). The developed method is an efficient diastereoselective‐cyclization method for the generation of C−N axial chirality. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Asian Journal of Organic Chemistry Wiley

Highly Efficient Syntheses of C−N Axially Chiral 1‐(ortho‐hydroxyaryl)uracil using a Chiral Auxiliary and a Chiral Base

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References (28)

Publisher
Wiley
Copyright
© 2018 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim
ISSN
2193-5807
eISSN
2193-5815
DOI
10.1002/ajoc.201800247
Publisher site
See Article on Publisher Site

Abstract

We achieved a highly diastereoselective synthesis of 1‐aryl‐6‐aminouracils, which are C−N atropisomeric compounds, through the combined use of a chiral auxiliary and a chiral base under mild conditions. We found that the (R)‐5‐allyl‐2‐oxabicyclo[3.3.0]oct‐1‐yl group is a good chiral auxiliary that, when combined with quinidine, efficiently affords 1‐aryl‐6‐aminouracils with high diastereoselectivity (up to 98 % ee after isolation). The chiral alcohol moiety in quinidine appears to be crucial for achieving stereoselectivity during cyclization. Furthermore, the chiral auxiliary was easily removed from the product under acidic conditions to provide the atropisomer with high enantiomeric excess (up to 96 % ee). The developed method is an efficient diastereoselective‐cyclization method for the generation of C−N axial chirality.

Journal

Asian Journal of Organic ChemistryWiley

Published: Aug 1, 2018

Keywords: ; ; ; ; ;

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