Diels–Alder reactions of chromone-3-carboxaldehydes with ortho-benzoquinodimethane. New synthesis of benzo [b] xanthones

A Sandulache, AMS Silva, JAS Cavaleiro

Index: Sandulache, Angela; Silva, Artur M.S; Cavaleiro, Jose A.S Tetrahedron, 2002 , vol. 58, # 1 p. 105 - 114

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Citation Number: 42

Abstract

An efficient new route to the benzo [b] xanthone system has been developed and applied to the synthesis of several new derivatives. The cycloaddition reactions of chromone-3- carboxaldehydes 12, reacting as dienophiles, with ortho-benzoquinodimethane 7 gave a diastereomeric mixture of cycloadducts 8 and 9. The formation of these compounds results from the Diels–Alder reactions of 12 and 7 followed by the in situ deformylation. The ...