Rhodium-Catalyzed Oxidative C–H Allylation of Benzamides with 1,3-Dienes by Allyl-to-Allyl 1,4-Rh(III) Migration
作者:Stamatis E. Korkis、David J. Burns、Hon Wai Lam
DOI:10.1021/jacs.6b06884
日期:2016.9.21
oxidative C-H allylation of N-acetylbenzamides with 1,3-dienes is described. The presence of allylic hydrogens cis to the less substituted alkene of the 1,3-diene is important for the success of these reactions. With the assistance of reactions using deuterated 1,3-dienes, a proposed mechanism is provided. The key step is postulated to be the first reported examples of allyl-to-allyl 1,4-Rh(III) migration
Synthesis of Spiropentadiene Pyrazolones by Rh(III)-Catalyzed Formal sp<sup>3</sup> C–H Activation/Annulation
作者:Jiuan Zheng、Panpan Li、Meng Gu、Aijun Lin、Hequan Yao
DOI:10.1021/acs.orglett.7b00930
日期:2017.6.2
pyrazolones with alkynes has been developed. This reaction provides a convenient route to synthesize spiropentadiene pyrazolones in good to excellent yields at room temperature, exhibiting good functional group tolerance, gram scalability, and high regioselectivity. Of note, the α-arylidene pyrazolone was introduced as a novel C3 synthon in C–H activation/annulation.
two‐carbon (C2) cyclization buildingblock. The present protocol successfully inhibits the competitive cycloaddition with the C≡N bond of acetonitrile, but enables the in situ formation of an unsaturated carbon–carbonbond and the subsequent cycloaddition as a C2 unit. This chemistry features simple reaction conditions, high chemoselectivities, wide substrate scope, and offers a new and practical approach
One-Carbon Oxidative Annulations of 1,3-Enynes by Catalytic C−H Functionalization and 1,4-Rhodium(III) Migration
作者:Johnathon D. Dooley、Hon Wai Lam
DOI:10.1002/chem.201706043
日期:2018.3.15
Rhodium(III)‐catalyzed C−H functionalization‐oxidativeannulations of aromatic substrates with 1,3‐enynes that contain allylic hydrogen atoms cis to the alkyne are described. The key step in these reactions is an alkenyl‐to‐allyl 1,4‐rhodium(III) migration to give electrophilic π‐allylrhodium(III) species. Nucleophilic trapping of these species gives heterocycles such as benzopyrans, isobenzofuranones
Regioselective Synthesis of 3-Hydroxy-4,5-alkyl-Substituted Pyridines Using 1,3-Enynes as Alkynes Surrogates
作者:Manuel Barday、Kelvin Y. T. Ho、Christopher T. Halsall、Christophe Aïssa
DOI:10.1021/acs.orglett.6b00451
日期:2016.4.15
The poor regioselectivity of the [4 + 2] cycloaddition of 3-azetidinones with internal alkynes bearing two alkyl substituents via nickel-catalyzed carbon–carbon activation is addressed using 1,3-enynes as substrates. The judicious choice of substitution on the enyne enables complementary access to each regioisomer of 3-hydroxy-4,5-alkyl-substituted pyridines, which are important building blocks in