Intramolecular Diels–Alder Reactions: Diastereofacial Selectivity and Coupling with an Aliphatic Claisen Rearrangement

Five from one!—this is the bottom line in the transformation of 1 into 4, where one stereocenter induces four new ones. The allyl alcohol 1 is converted into the ester 2 with sorbic acid, which then cyclizes to 3 in an intramolecular Diels–Alder reaction (“CO → CC induction”). In a simple reaction sequence compound 3 opens to 4, which contains five distinct hydroxy functions and is therefore an attractive building block for synthesis.