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A Lewis acid-mediated cascade annulation of o-alkoxy alkynols in the presence of ZnBr2 has been developed. The cascade cyclization proceeds through a 5-exo-dig cyclization followed by a Friedel-Crafts reaction and… Click to show full abstract
A Lewis acid-mediated cascade annulation of o-alkoxy alkynols in the presence of ZnBr2 has been developed. The cascade cyclization proceeds through a 5-exo-dig cyclization followed by a Friedel-Crafts reaction and ring-opening sequence to synthesize indeno[1,2-c]chromenes. This protocol provides a broad substrate scope in moderate to good yields with high regioselectivity. The reaction with benzo-fused cycloalkyl ketones gave an unexpected alkyne C-C bond cleavage resulting in fused polycycles.
Keywords:
indeno chromenes;
alkoxy alkynols;
znbr2 mediated;
reaction;
mediated cascade
Journal Title: Organic letters
Year Published: 2017
Link to full text (if available)
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Journal Title: Organic letters
Year Published: 2017
Link to full text (if available)
Share on Social Media: Sign Up to like & get
recommendations!