A New Synthesis of Aldehydes by the Palladium-Catalyzed Reaction of 2-Pyridinyl Esters with Hydrosilanes
Jun Nakanishi, Hiroto Tatamidani, Yoshiya Fukumoto, Naoto Chatani*
*Department of Applied Chemistry, Faculty of Engineering, Osaka University,
Suita, Osaka 565-0871, Japan, Email: chatani
chem.eng.osaka-u.ac.jp
J. Nakanishi, H. Tatamidani, Y. Fukumoto, N. Chatani, Synlett, 2006, 869-872.
DOI: 10.1055/s-2006-939058
Abstract
A palladium-catalyzed reduction of 2-pyridinyl esters using hydrosilanes is applicable to the preparation of aliphatic, aromatic, and α,β-unsaturated aldehydes. Various functional groups, such as fluoro, methoxy, aldehyde, acetal, and ester, are tolerated.
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Details
The document describes a new method for synthesizing aldehydes using a palladium-catalyzed reaction of 2-pyridinyl esters with hydrosilanes. This reaction is effective for producing aliphatic, aromatic, and α,β-unsaturated aldehydes and is compatible with various functional groups such as fluoro, methoxy, aldehyde, acetal, and ester. The method avoids the use of acid chlorides, which are difficult to handle and prone to racemization. Instead, 2-pyridinyl esters are used, which are more stable and reactive under the reaction conditions. The reaction involves treating 2-pyridinyl esters with triethylsilane (TES) in the presence of Pd(OAc)2 and PPh3 in DMF at 60°C for 12 hours, yielding high-purity aldehydes. The presence of PPh3 is crucial for the reaction's success, and the use of other solvents or hydrosilanes results in lower yields. Control experiments showed that the 2-pyridinyl group is essential for the reaction, as other esters were unreactive. The method is efficient and practical, providing a valuable alternative to traditional aldehyde synthesis methods.
Key Words
catalysis, 2-pyridinyl esters, triethylsilane, aldehydes, palladium
ID: J60-Y2006-4350
