Construction of Multi-Substituted Benzenes via NHC-Catalyzed Reactions of Carboxylic Esters
作者:Jichang Wu、Chengli Mou、Yonggui Robin Chi
DOI:10.1002/cjoc.201700773
日期:2018.4
A carbene‐catalyzed ester activation reaction for the synthesis of multi‐substituted benzenes is developed. Tetra‐substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than
N-Heterocyclic Carbene Catalyzed Cyclocondensation of α,β-Unsaturated Carboxylic Acids: Enantioselective Synthesis of Pyrrolidinone and Dihydropyridinone Derivatives
作者:Xiang-Yu Chen、Zhong-Hua Gao、Chun-Yu Song、Chun-Lin Zhang、Zhi-Xiang Wang、Song Ye
DOI:10.1002/anie.201407469
日期:2014.10.20
The catalytic cyclocondensation of in situ activated α,β‐unsaturated carboxylic acids was developed. N‐heterocyclic carbenes efficiently catalyzed the generation of α,β‐unsaturated acyl azolium intermediates from α,β‐unsaturated carboxylic acids via in situgenerated mixed anhydrides for the enantioselective [3+2] and [3+3] cyclocondensation with α‐amino ketones and alkyl(aryl)imines, respectively
N-Heterocyclic carbene-catalyzed [4 + 2] cyclization of α,β-unsaturated carboxylic acids bearing γ-H with isatins: an enantioselective synthesis of spirocyclic oxindole–dihydropyranones
作者:Ling Zhu、Chenxia Yu、Tuanjie Li、Yuhong Wang、Yinan Lu、Wenjing Wang、Changsheng Yao
DOI:10.1039/c5ob02160j
日期:——
An NHC-catalyzed asymmetric [4 + 2] annulation of isatins and α,β-unsaturated carboxylicacids bearing γ-H gave spirocyclic oxindole–dihydropyranones successfully via an in situactivationstrategy. This protocol featured easy availability of raw materials, good yields and excellent enantioselectivities (up to 99% ee).
A Pd-catalyzed decarboxylative cross-coupling of α,β-unsaturatedcarboxylicacids with cyclic and acyclic epoxides has been developed. Both β-monosubstituted and β-disubstituted unsaturated carboxylicacids, as well as conjugated diene unsaturated carboxylicacids are suitable reaction substrates. Substituted homoallylic alcohols were obtained in moderate to good yields. The product was obtained as
Fe(III)/Pyridine-Mediated Decarboxylative Nitration of α,β-Unsaturated Acids with Iron Nitrate
作者:Tao Yang、Congshan Zhou、Zan Yang、Jiao Li、Jie Hua、Jianmin Yi
DOI:10.1055/s-0036-1588948
日期:——
A novel and efficient method for the synthesis of (E)-nitroolefins in moderate to excellent yields is developed by Fe(III)/pyridine-mediated decarboxylative nitration of α,β-unsaturated acids with iron nitrate. A series of α,β-unsaturated acids are well tolerated in this procedure.