18386-00-0Relevant academic research and scientific papers
Application of E1cB Elimination in Asymmetric Organocatalytic Cascade Reactions to Construct Polyheterocyclic Compounds
You, Zhi-Hao,Chen, Ying-Han,Tang, Yu,Liu, Yan-Kai
supporting information, p. 8358 - 8363 (2019/10/16)
By introducing a carbon functionality at 2-position of chromane, the formal asymmetric functionalization of the 3-position of 2-substituted chromane has been realized via a highly chemo-, regio-, and stereoselective organocatalytic cascade reaction in a sequential one-pot manner involving an E1cB mechanism governed ring-opening process. Critical to our success was the design of a chiral dipeptide-based bifunctional acid-base organocatalyst, which exhibited high catalytic activity at low catalyst loading (1-0.1 mol %), leading to biologically interesting polyheterocyclic compounds.
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with o-hydroxycinnamaldehydes: Synthesis of 2,4-disubstituted chromans
Maity, Rajendra,Pan, Subhas Chandra
supporting information, p. 1598 - 1608 (2018/03/08)
An organocatalytic asymmetric cascade Michael/hemiketalization/acyl transfer reaction between o-hydroxycinnamaldehydes and α-nitroketones is developed. Prolinol TMS ether catalyst in combination with benzoic acid was found to be the most effective for this reaction which proceeds through an equilibrium of lactols to provide a single diastereomer of enantiopure 2,4-disubstituted chromans.
Bi(OTf)3-catalyzed addition of isocyanides to 2: H -chromene acetals: An efficient pathway for accessing 2-carboxamide-2 H -chromenes
Lyu, Longyun,Jin, Ming Yu,He, Qijie,Xie, Han,Bian, Zhaoxiang,Wang, Jun
supporting information, p. 8088 - 8091 (2016/09/09)
Bismuth triflate (Bi(OTf)3) is identified as an efficient catalyst for the direct addition of isocyanides to 2H-chromene acetals. The large scope of isocyanides and chromene acetals makes them suitable substrates in this catalytic system. By this synthetic strategy, a polyfunctional molecular scaffold, 2-carboxamide-2H-chromenes could be prepared efficiently in one step up to 95% yield. In addition, this efficient and practical protocol proceeded smoothly in the gram scale even when the catalytic loading was reduced to 2 mol%.
Trimethylsilyl iodide mediated one-pot synthesis of 2-allyl-2H-chromenes
Padhi, Birakishore,Reddy, D. Srinivas,Mohapatra, Debendra K.
, p. 542 - 547 (2015/01/30)
A new and efficient metal-free trimethylsilyl iodide (TMSI) catalyzed one-pot synthesis of 2-allyl-2H-chromenes has been developed that takes place under mild conditions. The synthesis proceeds through a Wittig reaction by using (triphenylphosphoranylidene)acetaldehyde to form an ohydroxycinnamaldehyde derivative followed by a tandem isomerization and C-O and C-C bond-forming reactions. The procedure was carried out at room temperature in the presence of 20 mol-% of TMSI and allyltrimethylsilane in tetrahydrofuran (THF) and provided the 2-allyl-2H-chromenes in good to excellent yields.
