Asymmetric C-C Bond Formation between Chiral N-Phosphonyl Imines and Ni(II)-Complex of Glycine Schiff Base Provides a GAP Synthesis of α,β-syn-Diamino Acid Derivatives

Asymmetric aza-Morita–Baylis–Hillman reactions of chiral N-phosphonyl imines with acrylates via GAP chemistry/technology

A series of aza-Morita–Baylis–Hillman acrylates have been synthesized by using chiral N-phosphonyl imines and GAP chemistry/technology.

Cobalt-catalysed site-selective intra- and intermolecular dehydrogenative amination of unactivated sp(3) carbons

Cobalt-catalysed sp² C–H bond functionalization has attracted considerable attention in recent years because of the low cost of cobalt complexes and interesting modes of action in the process. In comparison, much less efforts have been devoted to the sp³ carbons. Here we report the cobalt-catalysed site-selective dehydrogenative cyclization of aliphatic amides via a C–H bond functionalization process on unactivated sp³ carbons with the assistance of a bidentate directing group. This method provides a straightforward synthesis of monocyclic and spiro β- or γ-lactams with good to excellent stereoselectivity and functional group tolerance. In addition, a new procedure has been developed to selectively remove the directing group, which enables the synthesis of free β- or γ-lactam compounds. Furthermore, the first cobalt-catalysed intermolecular dehydrogenative amination of unactivated sp³ carbons is also realized.

Functionalizing unactivated carbon–hydrogen bonds is challenging, especially when using non-precious metals and dealing with sp³ hybridized carbons. Here, the authors report an intramolecular cobalt catalysed amination of C–H bonds of sp³ carbons, giving access to β- and γ-lactams.

N-Phosphonyl/phosphinyl imines and group-assisted purification (GAP) chemistry/technology

Group-assisted purification (GAP) chemistry, which can provide various chiral amines and other functionalities without the use of column chromatography or recrystallization; products are consistently obtained with excellent stereocontrol.

Solution-phase-peptide synthesis via the group-assisted purification (GAP) chemistry without using chromatography and recrystallization

The solution phase synthesis of N-protected amino acids and peptides has been achieved through the Group-Assisted Purification (GAP) chemistry by avoiding disadvantages of other methods in regard to the difficult scale-up, expenses of solid and soluble polymers, etc. The GAP synthesis can reduce the use of solvents, silica gels, energy and manpower. In addition, the GAP auxiliary can be conveniently recovered for re-use and is environmentally friendly and benign, and substantially reduces waste production in academic labs and industry.