Lossen Rearrangement vs C–N Reductive Elimination Enabled by Rh(III)-Catalyzed C–H Activation/Selective Lactone Ring-Opening: Chemodivergent Synthesis of Quinolinones and Dihydroisoquinolinones
作者:Mengyao Bian、Hamdulla Mawjuda、Hui Gao、Huiying Xu、Zhi Zhou、Wei Yi
DOI:10.1021/acs.orglett.0c03734
日期:2020.12.18
An unprecedented Rh(III)-catalyzed cascade C–H activation/Lossen rearrangement of aromatic amides with methyleneoxetanones has been realized along with a tunable C–N bond reductive elimination/trans esterification, giving divergent access to quinolinones and dihydroisoquinolinones via selective ring-opening of the four-membered lactone unit. Combined computational and experimental mechanistic studies
Synergistic Dual Directing Groups-Enabled Diastereoselective C–H Cyclopropylation via Rh(III)-Catalyzed Couplings with Cyclopropenyl Alcohols
作者:Min Wu、Shuang Lin、Guoxun Zhu、Ming Sun、Zhi Zhou、Hui Gao、Wei Yi
DOI:10.1021/acs.orglett.9b04608
日期:2020.2.21
By using a synergisticdualdirecting group-assisted C-H activation strategy and simply modifying the reaction conditions, we realized a robust and general Cp*Rh(III)-catalyzedC-Hcyclopropylation of N-acetoxybenzamides with cyclopropenylalcohols, providing regio-, chemo-, and diastereoselective access to ortho trans- and cis-1,1-dimethylcyclopropane-functionalized benzamides in a redox-neutral and
Rhodium(<scp>iii</scp>)-catalyzed formal oxidative [4 + 1] cycloaddition of benzohydroxamic acids and α-diazoesters. A facile synthesis of functionalized benzolactams
A Rh(III)-catalyzed oxidative [4 + 1] cycloaddition of benzohydroxamic acids and α-diazoesters is achieved to afford benzolactams in up to 93% yields. With the N-OAc amido moiety as a directing group, the ortho-C–H is selectively functionalized and the catalytic reaction exhibits excellent tolerance to different functional substituents. A notable rhodacyclic complex is isolated and structurally characterized
Hypervalent iodine(<scp>iii</scp>)-mediated oxidation of aldoximes to N-acetoxy or N-hydroxy amides
作者:Harisadhan Ghosh、Bhisma K. Patel
DOI:10.1039/b917096k
日期:——
hypervalent iodine(III) reagents (diacetoxyiodo)benzene (DIB) or Koser's reagent [hydroxy(tosyloxy)iodo]benzene (HTIB) gave, respectively, N-acetoxy or N-hydroxy amides in good yields rather than the expected nitrile oxide dimerised product oxadiazole-N-oxides reported to be formed with other oxidising and hypervalent iodinereagents. The acetate or the hydroxyl group of DIB or HTIB attacks on the aryl/alkylnitrile