One-pot synthesis of β-amino esters from aldehydes using lanthanide triflate as a catalyst

Cerium Chloride (CeCl3·7H2O) as a highly efficient catalyst for one-pot Three-Component Mannich reaction

“…10 However, the classical Mannich reaction is plagued by a number of serious disadvantages with limited applications. 11,12 Therefore, numerous modern versions of Mannich reaction have been developed to overcome the negative aspect of this classical method. In general, improved methodologies rely on two-component system using preformed electrophiles such as imines and stable nucleophiles such as enolates, enols, ethers and enamines, 13,14 but the preferable route is the use of a onepot three-component strategy as it facilitates wide range of structural variations, but these early three-component reactions were hampered due to a number of serious limitations.…”

Synthesis of Bis(indolyl)methanes Using Recyclable PEG-Supported Sulfonic Acid as Catalyst

“…However, many of these Lewis acids are deactivated or sometimes decomposed by nitrogen containing reactants. Even when the desired reactions proceed, more than stoichiometric amounts of Lewis acids are required [19]. These problems can be solved to some extent by using expensive lithium perchlorate.…”

A mild, expedient, solventless synthesis of bis(indolyl)alkanes using silica sulfuric acid as a reusable catalyst

“…However, many Lewis acids are prone to undergo decomposition in the presence of nitrogen containing reactants and this necessitates the use of excess and sometimes stoichiometric amount of Lewis acid catalyst. [8] To overcome such problems, recently Montmorillonite K-10, [9,2a] triphenylphosphonium perchlorate, lithium perchlorate, [10,11] iodine,[12] zeolites, [13] triflate of lanthanides [14] and cyanuric chloride [15] have been reported to catalyze this reaction. However, many of these reagents are expensive, [10,11,14] need longer reaction time and are not environmental friendly which warrants the development of a new, practical, economical and environmental friendly protocol for the synthesis of bis(indolyl)methanes.…”