58686-65-0Relevant academic research and scientific papers
Metal-Free Oxidative [5+1] Cyclization of 1,5-Enynes for the Synthesis of Pyrazine 1-Oxide
Xia, Xiao-Feng,Zhao, Mingming,He, Wei,Zou, Lianghua,San, Xinxin,Wang, Dawei
supporting information, p. 3621 - 3626 (2020/08/05)
A chemo-selective nitrosylation of 1,5-enynes via a sequence of NO radical incorporation and intramolecular radical cyclization was reported. The formation of two C?N bonds and one C?O bond make this [5+1] cycloaddition reaction an efficient approach to synthesize pyrazine 1-oxides in moderate to good yields. Metal-free, short reaction time and mild conditions render this strategy more practical, eco-friendly and convenient. Synthetic utility of this protocol is highlighted by scaffolds diversification. (Figure presented.).
Rh-Catalyzed Asymmetric Hydrogenation of β-Substituted-β-thio-α,β-unsaturated Esters: Expeditious Access to Chiral Organic Sulfides
Liu, Gang,Han, Zhengyu,Dong, Xiu-Qin,Zhang, Xumu
, p. 5636 - 5639 (2018/09/12)
Rh/bifunctional bisphosphine-thiourea ligand (ZhaoPhos)-catalyzed asymmetric hydorgenation of both (Z)- and (E)-isomers of β-substituted-β-thio-α,β-unsaturated esters was successfully developed. This new asymmetric catalytic methodology provided highly efficient access to two enantiomers of chiral organic sulfides ethyl β-substituted-β-thio-propanoates with excellent results (up to 99% yield and >99% ee for (Z)-substrates, up to 99% yield and 98% ee for (E)-substrates, TON up to 5000), which are important intermediates in organic synthesis.
Gold(I)/Chiral N,N′-Dioxide–Nickel(II) Relay Catalysis for Asymmetric Tandem Intermolecular Hydroalkoxylation/Claisen Rearrangement
Li, Jun,Lin, Lili,Hu, Bowen,Zhou, Pengfei,Huang, Tianyu,Liu, Xiaohua,Feng, Xiaoming
supporting information, p. 885 - 888 (2017/01/13)
A highly efficient asymmetric cascade reaction between alkynyl esters and allylic alcohols has been realized. Key to success was the combination of a hydroalkoxylation reaction catalyzed by a π-acidic gold(I) complex with a Claisen rearrangement catalyzed by a chiral Lewis acidic N,N′-dioxide–nickel(II) complex. A range of acyclic α-allyl β-keto esters were synthesized in high yields (up to 99 %) with good diastereoselectivities (up to 97:3) and excellent enantioselectivities (up to 99 % ee) under mild reaction conditions. These products can be easily transformed into optically active β-hydroxy esters, β-hydroxy acids, or 1,3-diols.
Copper(i)/phosphine-catalyzed tandem carboxylation/annulation of terminal alkynes under ambient pressure of CO2: One-pot access to 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones
Xie, Jia-Ning,Yu, Bing,Guo, Chun-Xiang,He, Liang-Nian
, p. 4061 - 4067 (2015/07/15)
An efficient method for the synthesis of 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones from CO2, terminal alkynes, EtBr, and NHPI (N-hydroxyphthalimide) was developed through a tandem carboxylation/annulation strategy catalyzed by a copper(i)/phosphine system. This one-pot multicomponent reaction was conducted at atmospheric CO2 pressure to afford the target products in good to excellent yields under mild conditions. Notably, a wide range of functional groups were tolerated in this procedure. This protocol with simultaneous formation of four novel bonds i.e. two C-C bonds and two C-O bonds represents an efficient methodology for upgrading CO2 into heterocycles.
Design and application of a low-temperature continuous flow chemistry platform
Newby, James A.,Blaylock, D. Wayne,Witt, Paul M.,Pastre, Julio C.,Zacharova, Marija K.,Ley, Steven V.,Browne, Duncan L.
, p. 1211 - 1220 (2014/12/10)
A flow reactor platform technology applicable to a broad range of low temperature chemistry is reported. The newly developed system captures the essence of running low temperature reactions in batch and represents this as a series of five flow coils, each with independently variable volume. The system was initially applied to the functionalization of alkynes, Grignard addition reactions, heterocycle functionalization, and heteroatom acetylation. This new platform has then been used in the preparation of a 20-compound library of polysubstituted, fluorine-containing aromatic substrates from a sequential metalation-quench procedure and can be readily adapted to provide gaseous electrophile inputs such as carbon dioxide using a tube-in-tube reactor.
Ruthenium-catalyzed asymmetric [2 + 2] cycloadditions between chiral acyl camphorsultam-substituted alkynes and bicyclic alkenes
Goodreid, Jordan,Villeneuve, Karine,Carlson, Emily,Tam, William
, p. 10002 - 10012 (2015/02/19)
Ruthenium-catalyzed asymmetric [2 + 2] cycloadditions between chiral acyl camphorsultam-functionalized alkynes and bicyclic alkenes were examined, providing adducts with complete exo stereoselectivity in good overall yield and enantioselectivity (up to 99% and 166:1, respectively), as well as appreciable diastereoselectivity (up to 163:1). The diastereoselectivity showed dependence on the solvent and temperature, as well as on the substitution pattern of the reacting alkyne and bicyclic alkene components. In general, higher diastereoselectivities were observed for reactions conducted in ethereal solvents and at lower temperatures between N-propynoyl camphorsultams and bicyclic alkenes.
