Numerous electrophilic thiocyano oxyfunctionalization reactions of alkenes have been achieved using N-thiocyano-dibenzenesulfonimide, which is a newelectrophilic thiocyanation reagent and could be easily prepared in two steps from dibenzenesulfonimide. This approach provides efficient, simple, and modular methods for the formation of SCN-containing heterocycles such as lactones, tetrahydrofurans,
A Catalyst-Controlled Enantiodivergent Bromolactonization
作者:Yuk-Cheung Chan、Xinyan Wang、Ying-Pong Lam、Jonathan Wong、Ying-Lung Steve Tse、Ying-Yeung Yeung
DOI:10.1021/jacs.1c05680
日期:2021.8.18
enantiodivergent bromolactonization of olefinicacids has been developed. Quinine-derived amino-amides bearing the same chiral core but different achiral aryl substituents were used as the catalysts. Switching the methoxy substituent in the aryl amide system from meta- to ortho-position results in a complete switch in asymmetric induction to afford the desired lactone in good enantioselectivity and yield
ZnI<sub>2</sub>/Zn(OTf)<sub>2</sub>-TsOH: a versatile combined-acid system for catalytic intramolecular hydrofunctionalization and polyene cyclization
作者:Ting-Hung Chou、Bo-Hung Yu、Rong-Jie Chein
DOI:10.1039/c9cc07242j
日期:——
combined-acid system using a zinc(II) salt [ZnI2 or Zn(OTf)2] and p-toluene sulfonic acid (TsOH) was investigated for catalytic cationic cyclizations, including intramolecular hydrocarboxylation, hydroalkoxylation, hydroamination, hydroamidation, hydroarylation and polyenecyclizations. This reaction provides easy access to five- and six-membered O- and N-containing saturated heterocyclic compounds, tetrahydronaphthalene
Organocatalytic Synthesis of Lactones by the Oxidation of Alkenoic Acids
作者:Ierasia Triandafillidi、Marianna Raftopoulou、Anatoli Savvidou、Christoforos G. Kokotos
DOI:10.1002/cctc.201700837
日期:2017.11.9
organocatalytic synthetic procedure for the synthesis of hydroxylactones from alkenoic acids is described. The reaction includes the activation of H2O2 by an organocatalyst (2,2,2‐trifluoromethylacetophenone), the oxidation of an olefinic group to the corresponding epoxide, and intramolecular lactonization to afford a variety of substituted γ‐ or δ‐lactones with multiple substitution patterns in good
沿着现代可持续氧化的路线,描述了一种绿色和温和的有机催化合成方法,用于从链烯酸合成羟基内酯。反应包括有机催化剂(2,2,2-三氟甲基苯乙酮)活化H 2 O 2,烯基氧化为相应的环氧化物以及分子内酯化以提供各种取代的γ-或δ-内酯多种替代模式,高到高产量。如果转化率是定量的,则在简单萃取后就可以得到高纯度的产物。试图使过程不对称的尝试取得了有限的成功。
Chiral Bifunctional Selenide Catalysts for Asymmetric Iodolactonizations
BINOL-derived chiral sulfide catalysts unexpectedly gave iodolactonization products in nearly racemic forms. The roles of chalcogenide moieties and hydroxy groups on bifunctional catalysts were investigated, and the importance of both a selenide moiety and a hydroxy group on chiral bifunctional selenide catalysts to achieve enantioselective iodolactonizations was clarified. An optimized chiral bifunctional