Photoinduced [3+2] Annulation of Alkene with o-Iodoanilines: An Expedient Approach to Indolines
作者:Wujiong Xia、Xinxin Zhao、Lin Guo、Chao Yang
DOI:10.1055/s-0040-1705963
日期:2021.4
A highly regioselective [3+2] cyclization of alkenes with 2-iodoanilines under the irradiation of UV light is described. This general, metal-free strategy facilitates the direct preparation of 2-mono-/disubstituted indolines as well as spiroindolines through alkene carboamination in one step. Mechanistic studies suggested that the photochemical protocol proceeded via a radical pathway.
A new chiral Brønsted acid, generated in situ from a chiral phosphoric acid boron (CPAB) complex and water, was successfully applied to asymmetric indole reduction. This "designer acid catalyst", which is more acidic than TsOH as suggested by DFT calculations, allows the unprecedented direct asymmetricreduction of C2-aryl-substituted N-unprotected indoles and features good to excellent enantioselectivities
Catalytic Aerobic Dehydrogenatin of
<i>N</i>
‐Heterocycles by
<i>N</i>
‐Hydoxyphthalimide
作者:Weidong Chen、Hao Tang、Weilin Wang、Qiang Fu、Junfei Luo
DOI:10.1002/adsc.202000767
日期:2020.9.21
Catalytic methods for the aerobic dehydrogenation of N‐heterocycles are reported. In most cases, indoles are accessed efficiently from indolines using catalytic N‐hydroxyphthalimide (NHPI) as the sole additive under air. Further studies revealed an improved catalytic system of NHPI and copper for the preparation of other heteroaromatics, for example quinolines.
Divergent Syntheses of Indoles and Quinolines Involving N1–C2–C3 Bond Formation through Two Distinct Pd Catalyses
作者:Su San Jang、Young Ho Kim、So Won Youn
DOI:10.1021/acs.orglett.0c02898
日期:2020.12.4
annulative couplings of 2-alkenylanilines with aldehydes using alcohols as both the solvent and hydrogen source have been developed. These domino processes allow divergent syntheses of two significant N-heterocycles, indoles and quinolines, from the same substrate by tuning reaction parameters, which seems to invoke two distinct mechanisms. The nature of the ligand and alcoholic solvent had a profound