TY - JOUR
T1 - Practical Organocatalytic Synthesis of Functionalized Non-C2-Symmetrical Atropisomeric Biaryls
AU - Gao, Hongyin
AU - Xu, Qing Long
AU - Keene, Craig
AU - Yousufuddin, Muhammed
AU - Ess, Daniel H.
AU - Kürti, Lászlõ
N1 - Funding Information:
Financial support from Rice University, National Institutes of Health (R01 GM-114609-01), National Science Foundation (CAREER:SusChEM CHE-1455335), the Robert A. Welch Foundation (Grant C-1764), ACS-PRF (Grant 51707-DNI1), and Amgen (2014 Young InvestigatorsI Award for L.K.) are greatly appreciated. D.H.E. thanks BYU and the Fulton Supercomputing Lab. X-Ray crystallographic data was obtained at the Center for Nanostructured Materials at the University of Texas at Arlington. We also express our gratitute to Professor John R. Falck (UT Southwestern Medical Center, Dallas, TX) for insightful discussions.
PY - 2016/1/11
Y1 - 2016/1/11
N2 - An organic acid catalyzed direct arylation of aromatic C(sp2)H bonds in phenols and naphthols for the preparation of 1,1′-linked functionalized biaryls was developed. The products are non-C2-symmetrical, atropoisomeric, and represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, is readily scaled up (up to 98mmol), and the structurally diverse 2,2′-dihydroxy biaryl (i.e., BINOL-type), as well as 2-amino-2′-hydroxy products (i.e., NOBIN-type) are formed with complete regioselectivity. Density-functional calculations suggest that the quinone and imino-quinone monoacetal coupling partners are exclusively arylated at their α-position by an asynchronous [3,3]-sigmatropic rearrangement of a mixed acetal species which is formed insitu under the reaction conditions. An organic acid catalyzed direct arylation of aromatic C(sp2)H bonds in phenols and naphthols was developed. This transformation is operationally simple, does not require an external oxidant, is readily scaled up, and the structurally diverse biaryls are formed with complete regioselectivity. Density functional calculations suggest a mechanism involving a mixed-acetal formation/[3,3]-sigmatropic rearrangement sequence.
AB - An organic acid catalyzed direct arylation of aromatic C(sp2)H bonds in phenols and naphthols for the preparation of 1,1′-linked functionalized biaryls was developed. The products are non-C2-symmetrical, atropoisomeric, and represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, is readily scaled up (up to 98mmol), and the structurally diverse 2,2′-dihydroxy biaryl (i.e., BINOL-type), as well as 2-amino-2′-hydroxy products (i.e., NOBIN-type) are formed with complete regioselectivity. Density-functional calculations suggest that the quinone and imino-quinone monoacetal coupling partners are exclusively arylated at their α-position by an asynchronous [3,3]-sigmatropic rearrangement of a mixed acetal species which is formed insitu under the reaction conditions. An organic acid catalyzed direct arylation of aromatic C(sp2)H bonds in phenols and naphthols was developed. This transformation is operationally simple, does not require an external oxidant, is readily scaled up, and the structurally diverse biaryls are formed with complete regioselectivity. Density functional calculations suggest a mechanism involving a mixed-acetal formation/[3,3]-sigmatropic rearrangement sequence.
KW - atropisomerism
KW - biaryls
KW - organocatalysis
KW - rearrangements
KW - synthetic methods
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U2 - 10.1002/anie.201508419
DO - 10.1002/anie.201508419
M3 - Article
C2 - 26592491
AN - SCOPUS:84958741433
VL - 55
SP - 566
EP - 571
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
SN - 1433-7851
IS - 2
ER -