Rhodium(III)-Catalyzed Dearomatizing (3 + 2) Annulation of 2-Alkenylphenols and Alkynes
摘要:
Appropriately substituted 2-alkenylphenols undergo a mild formal [3C+2C] cycloaddition with alkynes when treated with a Rh(III) catalyst and an oxidant. The reaction, which involves the cleavage of the terminal C-H bond of the alkenyl moiety and the dearomatization of the phenol ring, provides a versatile and efficient approach to highly appealing spirocyclic skeletons and occurs with high selectivity.
Cp*Co(III)-Catalyzed Dearomative [3 + 2] Spiroannulation of 2-Alkenylphenols with Ynamides via C–H Activation
作者:Peng-Peng Lin、Xiang-Lei Han、Guo-Hua Ye、Ji-Lin Li、Qingjiang Li、Honggen Wang
DOI:10.1021/acs.joc.9b01750
日期:2019.10.18
An oxidative [3 + 2] C-H spiroannulation reaction of 2-alkenylphenols with ynamides has been developed toward the synthesis of spiro[4,5]decane derivatives. This dearomative reaction employs earth-abundant cobalt as the metal catalyst and occurs under rather mild reaction conditions (room temperature). The use of ynamides confers unique reactivity and exclusive regioselectivity. The products bearing
Palladium(II)-Catalyzed Annulation between <i>ortho</i>-Alkenylphenols and Allenes. Key Role of the Metal Geometry in Determining the Reaction Outcome
作者:Noelia Casanova、Karina P. Del Rio、Rebeca García-Fandiño、José L. Mascareñas、Moisés Gulías
DOI:10.1021/acscatal.6b00739
日期:2016.5.6
2-Alkenylphenols react with allenes, upon treatment with catalytic amounts of Pd(II) and Cu(II), to give benzoxepine products in high yields and with very good regio- and diastereoselectivities. This contrasts with the results obtained with Rh catalysts, which provided chromene-like products through a pathway involving a β-hydrogen elimination step. Computational studies suggest that the square planar
Rhodium-Catalyzed (5+1) Annulations Between 2-Alkenylphenols and Allenes: A Practical Entry to 2,2-Disubstituted 2<i>H</i>-Chromenes
作者:Noelia Casanova、Andrés Seoane、José L. Mascareñas、Moisés Gulías
DOI:10.1002/anie.201410350
日期:2015.2.16
alkenylphenols react with allenes under rhodiumcatalysis to provide valuable 2,2‐disubstituted 2H‐chromenes. The whole process, which involves the cleavage of one CH bond of the alkenyl moiety and the participation of the allene as a one‐carboncycloaddition partner, can be considered a simple, versatile, and atom‐economical (5+1) heteroannulation. The reaction tolerates a broad range of substituents
Rhodium-Catalyzed Coordination-Assisted Regioselective and Migratory Three-Point Double Annulation of <i>o</i>-Alkenyl Phenols with Tertiary Propargyl Alcohols
disclose herein a Rh(III)-catalyzed migratory three-point double annulation of o-alkenyl phenols with propargyl alcohols for de novo construction of naphtho furan derivatives in a regio- and chemoselective manner. The protocol orchestrates two new rings with four new bonds in one operation without the need for any additive. Necessary labeled and control experiments are conducted to elucidate the reaction