Diastereoselective Spirocyclization: Entry to Spirocyclic Diketopiperazines.

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Synthetic Chemistry

Background:

• Diketopiperazine (DKP) scaffolds are prevalent in natural products and pharmaceuticals.
• Accessing novel DKP-containing spirocyclic systems remains a synthetic challenge.

Purpose of the Study:

• To develop a novel synthetic strategy for constructing spirocyclic compounds featuring a fused diketopiperazine-pyrrolidine motif.
• To explore the stereochemical outcomes and generality of the developed methodology.

Main Methods:

• Acid-catalyzed cyclization of a chiral aminoamide onto a 2,3-dehydroproline amide.
• Stereoselective introduction of a C-N bond at the spirocyclic center.
• Evaluation of substrate scope and substituent effects on stereoselectivity.

Main Results:

• A novel method for synthesizing spirocyclic diketopiperazines was established.
• High diastereoselectivity (>98:2) was achieved in the key cyclization step.
• The methodology demonstrated generality and applicability to diverse DKP-containing structures.

Conclusions:

• The developed approach provides efficient access to an underexplored class of spirocyclic diketopiperazines.
• This methodology holds potential for the discovery of new bioactive molecules.
• Stereochemical control can be modulated by substituent bulk on the aminoamide.