l-Proline catalysed asymmetric aldol reactions in PEG-400 as recyclable medium and transfer aldol reactions

Use of (S)‐5‐(2‐Methylpyrrolidin‐2‐yl)‐1H‐tetrazole as a Novel and Enantioselective Organocatalyst for the Aldol Reaction

“…[31] The product was obtained in 85 % ee. The optical purity was determined by HPLC with hexane/2-propanol (95:5) as eluent; flow rate 0.5 mL/min; t R = 52.87 min (R), 60.81 min (S).…”

Poly Ethylene Glycols as Efficient Media for the Synthesis of <i>β</i>-Nitro Styrenes from <i>α</i>, <i>β</i>-Unsaturated Carboxylic Acids and Metal Nitrates under Conventional and Non-Conventional Conditions

“…Recently we have concentrated on developing new methodologies using non-conventional energy sources and eco-friendly materials as catalysts in organic transformations, and reported a methodology in metal ion mediated nitration of organic compounds in presence of small amount of HNO 3 under solvent free (solid state) conditions [28]. Polyethylene glycol (PEG-400) is a biologically acceptable inexpensive polymer and an ecofriendly reagent [29], which is widely used in many organic reactions for conversion of oxiranes to thiiranes [30], asymmetric aldol reactions [31], cross-coupling reactions [18], Baylis-Hillman reaction [32,33] and ring opening of epoxides [34]. Encouraged by these results, we want to explore, the use of Polyethylene glycols (PEGs) as efficient catalyst in this study.…”

L-Proline catalyzed aldol reactions between acetone and aldehydes in supercritical fluids: An environmentally friendly reaction procedure

“…Large amounts of organic solvents are used in chemical reactions, most of which are volatile, toxic, and flammable. Poly(ethylene glycol) was also used as a solvent in reactions between acetone and aldehydes (yield 94%, ee 67%) [13,14]. From the viewpoint of greener processes, the use of nonhazardous and renewable materials is one of the most significant goals of green chemistry.…”