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Published online: 29 October 2008 | doi:10.1038/nchina.2008.256

Organic synthesis: Carbon to carbon

Vicki Cleave

Introduction

© (2008) ACS

Making carbon–carbon bonds is a fundamental part of many organic synthesis routes, and the Tsuji–Trost reaction, which uses a palladium catalyst to link two carbons together, has been an important tool for this purpose. Now Zhangjie Shi at Peking University and co-workers¹ have broadened the variety of ways the reaction can be used.

It was previously observed that the Tsuji–Trost reaction would only proceed when one of the carbons to be joined was allylic (a carbon adjacent to a carbon–carbon double bond) and the other carbon was nucleophilic (a carbon that can donate electron pairs to form new bonds with other atoms). The allylic carbon would also need to be attached to a functional leaving group; the reaction would not proceed if the allylic carbon was attached to just hydrogen.

The researchers have circumvented the requirement for a leaving group in their reaction. They used a doubly charged palladium catalyst and found that the intermediate in the reaction is a palladium allyl complex. The method works for both intramolecular and intermolecular carbon bond formation; the intramolecular bonds create rings, in both aliphatic and aromatic molecules, by joining carbons.

Interestingly, the reaction is highly regio- and stereoselective — the products are mostly linear as opposed to branched, and predominantly trans bonds formed when both cis and trans are possible.

The authors of this work are from:
Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education, College of Chemistry and Molecular Engineering and Green Chemistry Center, Peking University, Beijing, China; State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.

Reference

1. Lin, S., Song, C. X., Cai, G. X., Wang, W. H. & Shi, Z. J. Intra/intermolecular direct allylic alkylation via Pd(II)-catalyzed allylic C–H Activation. J. Am. Chem. Soc. 130, 12901–12903 (2008).  | Article | PubMed | ChemPort |