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Sigmatropic Rearrangements of Hypervalent‐Iodine‐Tethered Intermediates for the Synthesis of Biaryls
Author(s) -
Hori Mitsuki,
Guo JingDong,
Yanagi Tomoyuki,
Nogi Keisuke,
Sasamori Takahiro,
Yorimitsu Hideki
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201801132
Subject(s) - sigmatropic reaction , chemistry , hypervalent molecule , regioselectivity , claisen rearrangement , bond cleavage , medicinal chemistry , stereochemistry , combinatorial chemistry , iodine , organic chemistry , catalysis
Metal‐free dehydrogenative couplings of aryliodanes with phenols to afford 2‐hydroxy‐2′‐iodobiaryls have been developed. This reaction proceeds through ligand exchange on the hypervalent iodine atom followed by a [3,3] sigmatropic rearrangement and with complete regioselectivity. This coupling, in combination with in situ oxidation by m CPBA, enables the convenient conversion of iodoarenes into desirable biaryls. The obtained biaryls have convertible iodo and hydroxy groups in close proximity, and are thus synthetically useful, as exemplified by the controlled syntheses of π‐extended furans and a substituted [5]helicene. DFT calculations clearly revealed that the rearrangement is sigmatropic, with C−C bond formation and I−O bond cleavage proceeding in a concerted manner. Acetic acid, which was found to be the best solvent for this protocol, renders the iodine atom more cationic and thus accelerates the sigmatropic rearrangement.