An efficient Friedel–Crafts alkylation of nitrogen heterocycles catalyzed by antimony trichloride/montmorillonite K-10

From Conventional Lewis Acids to Heterogeneous Montmorillonite K10: Eco‐Friendly Plant‐Based Catalysts Used as Green Lewis Acids

“…MK10 and metals were mixed together to obtain heterogeneous catalysts. Among them, ruthenium‐exchanged MK10 was used in the oxidation of alkyl arenes to aryl tert ‐butyl peroxides, Bi‐MK10 was employed in the nitration of arenes, Cd‐MK10 and Sb‐MK10 were studied as catalysts for the benzylation of benzene, and Ce 3+ ‐MK10 was studied in the acetalization of aldehydes and ketones . In particular, Ti 4+ ‐MK10 was used to develop a one‐pot, three‐step reaction consisting of 1) deacetalization–aldol condensation, Michael addition–acetalization; 2) esterification–aldol condensation–epoxidation, and 3) esterification–aldol condensation–Michael addition .…”

Methanesulfonic Acid‐Catalyzed One‐Pot Synthesis of 12‐Aryl or 12‐Alkyl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one Derivatives

“…During the past decade, methanesulfonic acid (GMA) has been reported as an inexpensive, readily biodegradable, nontoxic, commercially available, and environmentally benign catalyst for various organic transformations [28–32]. In the lights of our success in developing several catalytic system for organic reactions [33–38], herein, we wish to report a novel and high yielding solvent‐free method for the preparation of 12‐aryl or 12‐alkyl‐8,9,10,12‐tetrahydrobenzo[ a ]xanthen‐11‐one derivatives in the presence of GMA (Scheme 1).…”

Selective Synthesis of β‐Alkylpyrroles

“…However, as described in the previous paragraph, the preferential a-nucleophilicity of pyrroles actually makes the b-alkylation considerably difficult. In fact, a vast amount of research has thus far been devoted to exclusive or selective aalkylation of pyrroles, in which various organic molecules such as alkenes, [7] alcohols, [8] allylic acetates, [9] ketones, [10] imines, [11] epoxides, [12] aziridines [12] and diazo compounds [13] have been the alkylating agents of choices. Under such situation, how do you alkylate pyrroles at the b-position regioselectively?…”