Ytterbium(III) Bis(Perfluorooctanesulfonyl)Imide Catalyzed One-Pot Synthesis of Tetrahydrobenzo[b]Pyrans in Fluorous Biphase System

Abstract

Ytterbium(III) bis(perfluorooctanesulfonyl)imide [Yb(NPf 2 ) 3 ] has been prepared, and used as an efficient catalyst for the synthesis of 4H-benzo[b]pyran derivatives by a one-pot three-component condensation of aldehydes, active methylene compounds, and dimedone in a fluorous biphase system (FBS). The reaction proceeds smoothly and affords the corresponding 4H-benzo [b]pyrans in moderate to excellent yields. The catalyst is selectively dissolved in the fluorous phase, can be recovered simply by phase separation and reused several times without any obvious decrease of activity.

Preparation and characterization of graphitic carbon nitride-supported l-arginine as a highly efficient and recyclable catalyst for the one-pot synthesis of condensation reactions

“… Entry R Product Time (min) Mp (°C) Mp (°C, ref.) Yield (%) 1 H 9a 7 228–229 225–228 33 95 2 4-Cl 9b 10 210–212 211–213 33 97 3 4-NO 2 9c 15 178–179 177–179 34 88 4 2,4-Cl 9d 10 118–120 115–117 24 95 5 4-OH 9e 20 206–208 208–210 24 93 6 4-Me 9f. 30 217–220 220–221 35 91 7 3-NO 2 9g 20 206–207 206–209 34 93 8 …”

“…Hence, many efforts have been made to synthesize such high-yield compounds. There are various methods for the synthesis of these compounds using different catalysts such as MCM-41@Schiff base-Co (OAC) 2 23 , Yb (NPf 2 ) 3 24 , MCM-41@serine@Cu(II) 25 , titanium silicon oxide nanopowder 26 , Y(NO 3 ) 3 .6H 2 O 27 , etc. despite their numerous advantages, they have some limitations such as long reaction time, expensive reagents, and the possibility of their contamination in final products.…”

Palladium nanoparticles embedded in improved mesoporous silica: a pH‐triggered phase transfer catalyst for Sonogashira reaction

“…[11][12][13][14] More specifically, recent research indicates that template-containing mesoporous silica is an interesting composite for various applications. [24][25][26][27][28] However, while biphasic conditions facilitate separation of catalyst and product and catalyst reuse, multiple phases introduce kinetic barriers and mass transfer limitations. [21][22][23] It is even better that an extraction solvent can be avoided by developing biphasic catalytic protocols.…”

“…Although the use of fluorous biphase systems and ionic liquid biphase systems has attracted a great deal of attention, a water-based biphasic catalytic system remains the most interesting choice in view of its lower cost and it being less hazardous. [24][25][26][27][28] However, while biphasic conditions facilitate separation of catalyst and product and catalyst reuse, multiple phases introduce kinetic barriers and mass transfer limitations. An interesting approach is that of anchoring homogeneous catalysts to thermomorphic polymers that are completely water soluble at room temperature but become more lipophilic and migrate towards the organic phase at the higher temperatures used for the catalytic reaction.…”