Experimental and Computational Studies into an ATPH‐Promoted exo‐Selective IMDA Reaction: A Short Total Synthesis of Δ⁹‐THC

Reversal of fortune: The inherent cis stereoselectivity of an intramolecular Diels–Alder reaction is reversed through promotion with aluminum tris(2,6-diphenylphenoxide) (ATPH), allowing a total synthesis of the natural product Δ9-tetrahydrocannabinol (see scheme). Computational studies predict the experimental findings and shed light on the stereocontrolling influences at play in these Diels–Alder reactions. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.