Asymmetric Henry reaction catalyzed by chiral heterogeneous Betti baseligands

Henry reaction is one of the most famous methods for the formation of carbon-carbonbonds, which is carried out through the addition of nitroalkane compounds to carbonylcontainingcompounds such as aldehyde or ketone in the presence of a base and finally producesβ-Nitroalcohol compounds, which are valuable raw materialsare in organic synthesis [۱,۲]. Theimmobilization of chiral ligands on an inorganic substrate such as UiO-۶۶-NH۲, in order toprepare a heterogeneous chiral catalyst, has attracted much attention due to different advantagesof heterogeneous catalysts [۳]. Chiral Betti bases can be used as ligands in various reactions toinduce chirality [۴].In this work, racemic Betti bases were first synthesized by a multicomponentreaction between ۲-naphthol, benzaldehyde and pyrrolidine, and then the resulting enantiomerswere separated by diastereomeric crystallization method using L-tartaric acid in acetone. Next,the UiO-۶۶-NH۲ metal-organic framework was synthesized by solvothermal method and afterfunctionalization of it using ۲-chloroacetyl chloride, the synthesized chiral Betti ligand wasimmobilized on it. Finally, this heterogeneous chiral ligand was used in theasymmetricHenryreaction in order to chirality induction, which resulted in the synthesis of chiral β-Nitroalcoholproducts with good enantioselectivities and high yields (Scheme ۱).

کلیدواژه ها:

Chiral Betti base ، Heterogeneous catalyst ، Henry reaction ، Chiral β-nitroalcohol