01870nas a2200289   4500008004100000022001400041245013600055210006900191260000900260300001600269490000700285520090000292653001901192653001901211653002001230653001201250653001401262653001101276653002301287100002801310700002901338700001801367700002401385700002601409700002001435856012501455       2021                        eng d  a2155-543500aNi(II)-catalyzed intramolecular C-H/C-H oxidative coupling: an efficient route to functionalized cycloindolones and indenoindolones0 aNiIIcatalyzed intramolecular CHCH oxidative coupling an efficien  cOCT   a12384-123930 v113 aNickel(II)-catalyzed intramolecular C(sp(2))-H/C(sp(3))-H and C(sp(2))-H/C(sp(2))-H oxidative couplings in indoles are achieved via chelation assistance. These reactions provide access to biologically relevant five- and six-membered substituted cyclopentaindolones, carbazolones, and indenoindolones in high yields and good chemoselectivity employing an air-stable and defined nickel catalyst, (bpy)Ni(OAc)(2). The oxidative cyclizations proceeded either through a six-membered or an unconventional seven-membered nickelacycle. An extensive mechanistic investigation by experiments and theoretical calculations revealed a facile indole's C(2)-H nickelation and a rate-limiting reductive elimination process. This intramolecular oxidative cyclization operates via a probable Ni(II)/Ni(III) pathway involving single-electron oxidation of nickel without the participation of a carbon-based radical.10aC-H activation10acycloindolones10aindenoindolones10aindoles10aMechanism10aNickel10aoxidative coupling1 aAnkade, Shidheshwar, B.1 aSamal, Pragnya, Paramita1 aSoni, Vineeta1 aGonnade, Rajesh, G.1 aKrishnamurty, Sailaja1 aPunji, Benudhar  uhttp://library.ncl.res.in/content/niii-catalyzed-intramolecular-c-hc-h-oxidative-coupling-efficient-route-functionalized02001nas a2200205   4500008004100000022001400041245011000055210006900165260000800234520126500242653001901507653001201526653001401538653001901552653002601571100002601597700002401623700002001647856012801667       2024                        eng d  a1867-388000aPalladium-catalyzed regioselective C(4)-H fluoroalkoxylation of indoles through weak chelation assistance0 aPalladiumcatalyzed regioselective C4H fluoroalkoxylation of indo  cOCT3 a<p>
	Installing fluoroalkyl motifs into biorelevant indoles is particularly interesting due to their ubiquitous presence in drug molecules. Herein, we demonstrate the regioselective C4 fluoroalkoxylation of indoles using fluoroalcohols via palladium-catalyzed chelation-assisted C &amp; horbar;H activation. The weak chelating benzoyl moiety at the C3 position acts as a directing group for remote C(4)&amp; horbar;H fluoroalkoxylation of diversely substituted indoles. This methodology demonstrates a high level of regioselectivity and tolerates a range of crucial functional groups, yielding diverse trifluoroalkoxylated indoles in moderate to good yields. Removal of directing/protecting groups and further functionalization established the synthetic utility of the methodology. A preliminary mechanistic investigation is conducted by isolating the palladacycle intermediate and performing the deuterium scrambling study. The regioselective C4 fluoroalkoxylation of indoles with various fluoroalcohols is achieved by the palladium-catalyzed weak chelation assistance strategy. The reaction is compatible for a range of important functionalities and proceeds via the intermediacy of a six-membered palladacycle following a Pd(II)/Pd(IV) pathway. image</p>
10aC-H activation10aindoles10aPalladium10aRegioselective10aTrifluoroalkoxylation1 aVijaykumar, Muniyappa1 aGonnade, Rajesh, G.1 aPunji, Benudhar  uhttp://library.ncl.res.in/content/palladium-catalyzed-regioselective-c4-h-fluoroalkoxylation-indoles-through-weak-chelation