Ph3PAuNTf2 as a Superior Catalyst for the Selective Synthesis of 2H??Chromenes: Application to the Concise Synthesis of Benzopyran Natural Products

…, C Efe, C Gryparis, M Stratakis

Index: Lykakis, Ioannis N.; Efe, Christina; Gryparis, Charis; Stratakis, Manolis European Journal of Organic Chemistry, 2011 , # 12 p. 2334 - 2338

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Citation Number: 37

Abstract

Abstract Ph 3 PAuNTf 2 (≈ 1 mol-%) catalyzes the selective cycloisomerization of substituted aryl propargyl ethers into 2H-chromenes in excellent yields. Benzofuran byproducts are formed only in the case of electron-deficient arenes, in up to 7% relative yield. The Ph 3 PAuNTf 2-catalyzed cyclization of aryl propargyl ethers was applied as a key step to the concise synthesis of the naturally occurring benzopyrans seselin, xanthyletin, ...