TY - JOUR
T1 - Symmetry in Cascade Chirality-Transfer Processes
T2 - A Catalytic Atroposelective Direct Arylation Approach to BINOL Derivatives
AU - Wang, Jin Zheng
AU - Zhou, Jin
AU - Xu, Chang
AU - Sun, Hongbin
AU - Kürti, László
AU - Xu, Qing Long
N1 - Funding Information:
Financial support from the National Natural Science Foundation of China (81373303, 81473080, 81573299, and 21502230) is gratefully acknowledged. This project was also supported by the Jiangsu Province Natural Science Foundation (BK20150688), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT1193). L.K. gratefully acknowledges the generous financial support from Rice University, NIH (R01 GM-114609-01), NSF (CAREER:- SusChEM CHE-1455335), the Robert A. Welch Foundation (Grant C-1764), ACS-PRF (Grant 51707-DNI1), Amgen (2014 Young Investigators Award for L.K.), and Biotage (2015 Young Principal Investigator Award).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/4/27
Y1 - 2016/4/27
N2 - Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2′-dihydroxy-1,1′-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.
AB - Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2′-dihydroxy-1,1′-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.
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U2 - 10.1021/jacs.6b01458
DO - 10.1021/jacs.6b01458
M3 - Article
C2 - 27052566
AN - SCOPUS:84966378458
SN - 0002-7863
VL - 138
SP - 5202
EP - 5205
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 16
ER -