Base-catalyzed intramolecular condensation of tokinolide B.

• The novel pentacyclic compound cyclotokinolide B was obtained from the natural phthalide tokinolide B under basic conditions, via the chemoselective -enol lactone opening followed by a Michael addition of the generated carbanion to the enone and subsequent equilibration. This result confirms that some dimeric phthalides undergo intramolecular cyclizations in basic media.

Subject headings

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

Publication and Content Type

art (subject category)

ref (subject category)