A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed. Moreover, the various functionalities in the isoxazolidine products allow facile derivatization.
An efficient selective synthesis of C- and O-phosphoryl-substituted phenols from easily available diaryl H-phosphine oxides with quinone monoketals (QMAs) has been developed. With the assistance of opponent characteristic additives (e.g., H2O and Et3N), diaryl H-phosphine oxides could selectively proceed the allylic- and 1,6-substitution to conjugate with the C-/O- positions of QMAs. The reported protocol
Access to [4,3,1]-Bridged Carbocycles via Rhodium(III)-Catalyzed C–H Activation of 2-Arylindoles and Annulation with Quinone Monoacetals
作者:Guangfan Zheng、Xujing Duan、Lu Chen、Jiaqiong Sun、Shuailei Zhai、Xiaojiao Li、Jierui Jing、Xingwei Li
DOI:10.1021/acs.joc.0c00018
日期:2020.3.20
Reported herein is the Rh(III)-catalyzed annulation of N-unprotected 2-arylindoles with quinone monoacetals for the straightforward synthesis of [4,3,1]-bridged carbocycles with exclusive C(3) selectivity. Mechanistic studies, particularly deuterium-labeling experiments, suggest that the coupling likely proceeds via two-fold C-H activation with two-fold migratory insertion into the enone moieties.
Iodobenzene and m-chloroperbenzoic acid mediated oxidative dearomatization of phenols
作者:Neha Taneja、Rama Krishna Peddinti
DOI:10.1016/j.tetlet.2016.07.078
日期:2016.8
iodobenzene, and m-CPBA as a co-oxidant has been achieved via in situ generation of PhIO2, a hypervalent iodine(V) species. The transiently generated orthobenzoquinone monoketals further underwent Diels–Alderreaction with various dienophiles to furnish densely substituted bicyclo[2.2.2]octenones in high selectivities and yields. This methodology features ready availability of reagents, cost effectiveness, safety
Three‐Component Reaction of
<i>p</i>
‐Quinone Monoacetals, Amines and Diarylphosphine Oxides to Afford
<i>m‐</i>
(Phosphinyl)anilides
作者:Ruwei Shen、Xin Wang、Shunlin Zhang、Chao Dong、Dunru Zhu、Li‐Biao Han
DOI:10.1002/adsc.201901421
日期:2020.2.21
The three‐component reaction of p‐quinone monoacetals, amines and diarylphosphine oxides is developed to afford m‐(diarylphosphinyl)anilides in moderate to high yields. The reaction may proceed via a process involving phospha‐nucleophilic addition to an iminoquinone acetal intermediate and/or carbonyl‐amine condensation with a phosphinyl enone intermediate.