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[摘要]：Directed lithiation of p-tolyl 1-azulenyl sulfone at the 2-position of the azulenyl group was achieved by using lithium 2,2,6,6-tetramethylpiperidide (LTMP). The azulenyllithium thus generated could be efficiently trapped with various electrophiles to form 2-substituted azulenes I (R = Me3Si, PhS, iodo, CHO) in moderate to good yields. I (R = Me3Si) was transformed into a cyclic sulfone deriv. through the directed lithiation in the p-tolyl group and subsequent intramol. ring closure at the C-8 position. I (R = PhS) underwent desulfonylation to give 2-(phenylthio)azulene. The Suzuki coupling reaction of I (R = iodo) with arylboronic acids followed by desulfonylation efficiently gave 2-arylazulenes. |
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