Microwave-induced 1,3-dipolar intramolecular cycloadditions of N-substituted oximes, nitrones, and azomethine ylides for the chiral synthesis of functionalized nitrogen heterocycles
A report on the research efforts on the intramolecular cycloaddition reactions of oximes, nitrones, and azomethine ylides was presented. The oximes, nitrones, and azomethine ylides were derived from L-serine methyl ester on the surface of silica gel without a solvent under microwave irradiation. It resulted in the chiral preparation of functionalized tricyclic isoxazolidines fused with a pyrrolidine or piperidine ring.
Versatile approach for the synthesis of novel seven-membered iminocyclitols via ring-closing metathesis dihydroxylation reaction
Seven-membered iminocyclitols with diverse diastereomers were prepared starting with D- and L-serines and employing ring-closing olefin metathesis and dihydroxylation reaction sequence. The iminocyclitols were assayed for glycosidase inhibition and compound 20 was found to be a competitive inhibitor for β-glucosidase with Ki 26.3μM.
Synthesis of oxazolidinyl azacycles via ring-closing olefin metathesis: A practical entry to the synthesis of deoxy-azasugars and hydroxypyrrolizidines
Starting with D- and L-serines, an expedient method for the preparation of oxazolidinyl piperidines, azepenes and azacyclooctenes was illustrated as a route to various deoxy-azasugars and hydroxypyrrolizidines. The ring-closing olefin metathesis of oxazolidinyl di-olefins was used as a key-step to construct the azacycles. Consecutive epoxidation, hydrolysis and transannulation of oxazolidinyl azacyclooctene led to hydroxypyrrolizidines.