Solid-Phase Organic Synthesis and Catalysis: Some Recent Strategies Using Alumina, Silica, and Polyionic Resins

Abstract

Solid-phase organic synthesis (SPOS) and catalysis have gained impetus after the seminal discovery of Merrifield’s solid-phase peptide synthesis and also because of wide applicability in combinatorial and high throughput chemistry. A large number of organic, inorganic, or organic-inorganic hybrid materials have been employed as polymeric solid supports to promote or catalyze various organic reactions. This review article provides a concise account on our approaches involving the use of (i) alumina or silica, either having doped with metal salts or directly, and (ii) polyionic resins to either promote various organic reactions or to immobilize reagents/metal catalysts for subsequent use in hydrogenation and cross-coupling reactions. The reaction parameters, scopes, and limitations, particularly in the context of green chemistry, have been highlighted with pertinent approaches by other groups.

Solar-Driven Thermocatalytic Synthesis of Octahydroquinazolinone Using Novel Polyvinylchloride (PVC)-Supported Aluminum Oxide (Al2O3) Catalysts

“…However, metal leaching that typically accompanies this process prevents the reuse of these oxides, making them too expensive for large-scale applications. These issues can be overcome by employing inorganic (calcium carbonate, calcium kaolinites) and organic (such as polystyrene or divinylbenzene) polymers for promoting organic reactions [ 14 , 15 , 16 , 17 , 18 ]. The most optimal solid organic polymers for this purpose are chosen based on their stability and recyclability, as well as whether they bind with the substrate/reagent covalently or non-covalently [ 16 ].…”

Microwave‐heated γ‐Alumina Applied to the Reduction of Aldehydes to Alcohols

“…A number of heterogeneous catalysts have been developed for the MPV reduction, [19] such as, zeolites, [20][21][22][23][24][25] mesoporous silicates, [26] hydrotalcite, [27,28] metal oxides [29][30][31][32][33][34][35] or metal-organic frameworks. [36,37] However, most of them involve complex synthetic routes with the incorporation of various metals [24,25,38,39] and in some cases rare metals. [40] An inexpensive, readily available robust and non-toxic catalyst material for the heterogeneous MPV reduction would be highly desirable.…”

Silica-Mediated Synthesis of Indolinooxazolidine-Based Molecular Switches

“…Therefore, we decided to investigate the possibility of using silica as a mediator for the preparation of a large variety of indolinooxazolidines. Indeed, silica and alumina surfaces have already proved to be excellent mediators for a great variety of reactions, such as addition onto alkenes and alkynes, selective oxidations of S/N functionalities, , isomerizations and rearrangements, cross-coupling reactions, and Michael additions . The solid surface mediated approach continues to attract wider interest as it offers an environmentally benign way to synthesize certain compounds.…”