5-Aryloxazolidines as Reagents for Double Alkylation of Arenes: A Novel Synthesis of 4-Aryltetrahydroisoquinolines

Tunable Approach to Diverse Phenethylamines via Reduction of 5-Aryloxazolidines with Triethylsilane

A rapid pathway for the synthesis of various β-phenethylamines from aromatic aldehydes has been developed. Initially, a wide range of 5-aryloxazolidines was prepared via the [3 + 2] cycloaddition reaction of N-methylazomethine ylide derived from sarcosine and paraformaldehyde. The subsequent reduction of 5-aryloxazolidines with triethylsilane in trifluoroacetic acid yields three types of products: N,N-dimethylphenylethanolamines, N,N-dimethylphenethylamines, and tetrahydroisoquinolines, depending on the substituents in the aromatic ring and reaction conditions. Moreover, an additional step of oxazolidine hydrolysis or ring-opening with hydrogen cyanide allowed us to synthesize N-methyl- or N-methyl-N-(cyanomethyl)phenethylamines.

Synthesis of N-alkenylisoquinolinones via palladium-catalyzed cyclization/C4–O bond cleavage of oxazolidines

A palladium-catalyzed cascade ring-opening reaction to synthesize N-alkenylisoquinolinones via cyclization and C–O bond cleavage is reported.