A Highly Efficient and Practical Synthesis of Chromene Derivatives Using Ring-Closing Olefin Metathesis

Abstract

Chromenes (2H-1-benzopyran derivatives) have been widely employed as important intermediates in the synthesis of many natural products and medicinal agents. There has been recent interest in the use of these common structural elements for a new family of potassium-channel activating drugs. They also serve as the framework of a range of tannins, which are becoming increasingly important because of their health-promoting effects found in teas, vegetables, fruits, fruit juices, and red wines. Despite the several existing methods for the synthesis of chromene derivatives, there still is demand for general strategies which can efficiently provide variously substituted chromene systems. 
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\nIn this note, we report a practical and highly efficient procedure for preparing diverse chromene derivatives using ring-closing metathesis (RCM), a methodology emerging as a new tool in synthetic organic chemistry