Premium
Alkynylboronates and ‐boramides in Co I ‐ and Rh I ‐Catalyzed [2+2+2] Cycloadditions: Construction of Oligoaryls through Selective Suzuki Couplings
Author(s) -
Iannazzo Laura,
Vollhardt K. Peter C.,
Malacria Max,
Aubert Corinne,
Gandon Vincent
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201100371
Subject(s) - chemistry , intramolecular force , cycloisomerization , rhodium , catalysis , suzuki reaction , aryl , medicinal chemistry , cobalt , combinatorial chemistry , stereochemistry , organic chemistry , palladium , alkyl
Oligoaryls were prepared through transition‐metal‐catalyzed [2+2+2] cycloadditions of borylated alkynes, followed by Suzuki cross‐couplings with aryl halides. Ethynylboryl pinacolate took part in cobalt‐catalyzed [2+2+2] cycloadditions of all types investigated (i.e., all‐intermolecular cyclotrimerization, diyne‐yne cocyclization, and all‐intramolecular triyne cycloisomerization). The resulting platforms gave rise to linear and angular ter‐ and quateraryls after Pd‐catalyzed cross‐coupling. In addition, the first [2+2+2] cycloadditions involving alkynyl naphthaloboramides were developed. These derivatives could be cocyclized with diynes in the presence of a rhodium complex as catalyst. Because the boramide group is inactive under Suzuki coupling conditions, but can be readily deprotected to afford an active one, an iterative functionalization of a boronate‐/boramide‐substituted benzene could be achieved.