A bench-stable combination of NaBH4–acetylacetone was developed for the efficient chemoselective reduction of aldehydes in the presence of ketones.

A sequential process involving Boc-mediated oxidative dearomatization and inter/intramolecular Diels−Alder reaction was investigated. Based on an intermolecular Diels−Alder reaction and subsequently a radical 7-endo-trig type cyclization, the [6.6.7.5] tetracyclic core of Calyciphylline N was assembled.Letter pubs.acs.org/OrgLett