New Synthesis of 2-Oxo-3-alkenylphosphonates and Hetero Diels–Alder Reactions with Vinyl Ethers Leading to 5-Substituted 2-Phosphiny 1-2-cyclohexen-1-ones

E Wada, S Kanemasa, O Tsuge

Index: Wada, Eiji; Kanemasa, Shuji; Tsuge, Otohiko Bulletin of the Chemical Society of Japan, 1989 , vol. 62, # 3 p. 860 - 868

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Citation Number: 17

Abstract

A new method of synthesizing phosphinyl-substituted enones, 2-oxo-3- alkenylphosphonates, is developed via the dianion of diethyl 2-oxopropylphosphonate. The enones serve as hetero dienes in thermal reactions with vinly ethers producing 2-alkoxy-6- (phosphinylmethyl)-3, 4-dihydro-2H-pyrans. Acid-catalyzed cleavage of these cycloadducts is followed spontaneously by internal condensation furnishing 2-phosphinyl-2-cyclohexen ...