Stereoselective Direct
<i>N</i>
‐Trifluoropropenylation of Heterocycles with a Hypervalent Iodonium Reagent
作者:János T. Csenki、Ádám Mészáros、Zsombor Gonda、Zoltán Novák
DOI:10.1002/chem.202102840
日期:2021.11.11
E-selective trifluoropropenylation of versatile N-heterocycles was developed with the utilization of trifluoropropenyliodonium salts. The procedure enables the straightforward direct introduction of the trifluoroalkenyl moiety into heterocyclic scaffolds under simple and mild reaction conditions.
A direct catalytic asymmetric vinylogous Mannich-typereaction has been disclosed in good yield, excellent regio-, diastereo- and enantioselectivity. The key to control the regioselectivity is the combination of a bulky N-acylpyrazole and a bulky bisphosphine ligand. The catalytic system was extended to a bisvinylogous Mannich-typereaction by changing the ligand. The synthetic utility of the vinylogous
A novel strategy for the crossdehydrogenativecoupling (CDC) of acetophenone hydrazones and aldehydes has been developed for the synthesis of highly substituted pyrazoles. This work, for the first time, uses elemental sulfur as a promoter as well as a hydrogen acceptor in effecting the Csp(3)-Csp(2) bond formation via C-H activation.
Iron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate: Synthesis of 3,5-disubstituted 1H-pyrazoles
We have developed an iron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate. Various 3,5-disubstituted 1H-pyrazoles were obtained in good to excellent yields. This method offers several advantages, including room-temperature conditions, short reaction time, high yields, simple work-up procedure, and use of air as an oxidant. The catalyst
A catalytic asymmetric vinylogous Mannich-type reaction of γ-halo-α,β-unsaturated N-acylpyrazoles and N-Boc-aldimines was disclosed, which afforded an array of halogenated (F-, Cl-, and Br-) allylic stereogenic carbon centers in high yields with good to high regio-, diastereo-, and enantioselectivities. The brominated product served as a suitable electrophile for common SN2 nucleophilic substitution