A Concise Synthesis of Asymmetrically 4,5-Disubstituted 9,9-Dimethyl-9H-xanthenes

Abstract

A concise synthesis of asymmetrically 4,5-disubstituted 9,9-dimethyl-9H-xanthenes was developed. The monolithiation of 4,5-dibromo-9H-xanthene, subsequent zincation, and the Negishi coupling with diverse electrophiles afforded the corresponding 4-aryl- or 4-vinyl-9H-xanthenes in good yields and with high selectivity. The second substitution reactions were performed under mild reaction conditions, thus providing a convenient synthetic route to functionalized molecules based on the 9H-xanthene skeleton.

Key words

xanthenes - metalation - cross-coupling - palladium - zinc

• References

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