Development of a Practical and Scalable Preparation using Sonication of Pd/Fibroin Catalyst for Chemoselective Hydrogenation

Abstract

A practical and efficient preparation method of palladium‐fibroin (Pd/Fib), silk‐fibroin‐supported Pd(0) by means of sonication, has been developed. The Pd/Fib catalyst could be prepared within 12 h at room temperature starting from commercial silk‐fibroin and Pd(OAc)₂ in MeOH, whereas our previous preparation method required at least 4 days. The present improved process is applicable to a large‐scale preparation of Pd/Fib. The Pd/Fib prepared by the present method also catalyzed chemoselective hydrogenation of acetylenes, olefins, and azides in the presence of aromatic ketones, aldehydes, and halides; N‐Cbz protective groups; and benzyl esters, which are readily hydrogenated under the Pd/C‐ or Pd/C(en)‐catalyzed hydrogenation conditions.

Keywords:

• chemoselective
• hydrogenation
• Pd/fibroin
• practical
• sonication

Acknowledgment

This work was supported by the Research Foundation of Gifu Pharmaceutical University and Wako Pure Chemical Industries, Ltd.