Direct Alkylation of Amines with Primary and Secondary Alcohols through Biocatalytic Hydrogen Borrowing

The reductive aminase from Aspergillus oryzae (Asp RedAm) was combined with a single alcohol dehydrogenase (either metagenomic ADH‐150, an ADH from Sphingobium yanoikuyae (SyADH), or a variant of the ADH from Thermoanaerobacter ethanolicus (Te SADH W110A)) in a redox‐neutral cascade for the biocatalytic alkylation of amines using primary and secondary alcohols. Aliphatic and aromatic secondary amines were obtained in up to 99 % conversion, as well as chiral amines directly from the racemic alcohol precursors in up to >97 % ee , releasing water as the only byproduct.     

Iridium‐Catalyzed Asymmetric Allylic Dearomatization by a Desymmetrization Strategy

A desymmetrization strategy was developed involving iridium‐catalyzed allylic dearomatization of indoles. The six‐membered‐ring spiroindolenines contain three contiguous stereogenic centers, including an all‐carbon quaternary center, and were obtained in up to 99 % yield with 99 % ee and >95:5 d.r. When treated with a catalytic amount of tosylic acid, six‐membered spiroindolenine undergoes an unprecedented six‐to‐seven‐membered ring expansion, affording the corresponding hexahydroazepino[4,5‐b ]indole.