title: Practical Organocatalytic Synthesis of Functionalized Non-C2-Symmetrical Atropisomeric Biaryls.
abstract: An organic acid catalyzed direct arylation of aromatic C(sp(2))-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 98 mmol), 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 in situ under the reaction conditions.
authors.affiliation: Department of Chemistry, Rice University, BioScience Research Collaborative, 6500 Main Street, Rm 380, Houston, TX, 77030 (USA).
authors.forename: Hongyin
authors.initials: H
authors.lastname: Gao
authors.affiliation: Department of Chemistry, Rice University, BioScience Research Collaborative, 6500 Main Street, Rm 380, Houston, TX, 77030 (USA).
authors.forename: Qing-Long
authors.initials: QL
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Rice University, BioScience Research Collaborative, 6500 Main Street, Rm 380, Houston, TX, 77030 (USA).
authors.forename: Craig
authors.initials: C
authors.lastname: Keene
authors.affiliation: Life and Health Sciences Campus, The University of North Texas at Dallas, Dallas, TX 76016 (USA).
authors.forename: Muhammed
authors.initials: M
authors.lastname: Yousufuddin
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602 (USA).
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Ess
authors.affiliation: Department of Chemistry, Rice University, BioScience Research Collaborative, 6500 Main Street, Rm 380, Houston, TX, 77030 (USA).
authors.forename: László
authors.initials: L
authors.lastname: Kürti
mesh_terms: D018360:Crystallography, X-Ray; D006838:Hydrocarbons / Q000138:chemical synthesis* / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*
chemical_list: D006838:Hydrocarbons; D009930:Organic Chemicals
keywords: atropisomerism; biaryls; organocatalysis; rearrangements; synthetic methods