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Alkynyl Moiety for Triggering 1,2‐Metallate Shifts: Enantiospecific sp 2 –sp 3 Coupling of Boronic Esters with p ‐Arylacetylenes
Author(s) -
Ganesh Venkataraman,
Odachowski Marcin,
Aggarwal Varinder K.
Publication year - 2017
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.201703894
Subject(s) - pinacol , moiety , alkyne , chemistry , boron , boronic acid , medicinal chemistry , suzuki reaction , organic chemistry , palladium , catalysis
The enantiospecific coupling of secondary and tertiary boronic esters to aromatics has been investigated. Using p‐lithiated phenylacetylenes and a range of boronic esters coupling has been achieved by the addition of N‐bromosuccinimide (NBS). The alkyne functionality of the intermediate boronate complex reacts with NBS triggering the 1,2‐migration of the group on boron to carbon giving a dearomatized bromoallene intermediate. At this point elimination and rearomatization occurs with neopentyl boronic esters, giving the coupled products. However, using pinacol boronic esters, the boron moiety migrates to the adjacent carbon resulting in formation of ortho boron‐incorporated coupled products. The synthetic utility of the boron incorporated product has been demonstrated by orthogonal transformation of both the alkyne and boronic ester functionalities.