This document does not have an outline. ... JavaScript is disabled on your browser. Please enable JavaScript to use all the features on this page. ... Author links open the overlay panel. Numbers correspond to the affiliation list which can be exposed by using the show more link. ... Treatment of 2,2-dimethyl-3-iodochroman-5-ols (6) and (7) with KOH supported on Al 2 O 3 gives acid-sensitive spirodienones (8) and (9); the possible biosynthetic significance of this model reaction is ...