Cyclization of cembrane diterpenoids VII. Experimental confirmation of the scheme of acid-catalyzed cyclization of 5β-acetoxyisocembrol

It has been established that during the cyclization of 5β-acetoxyisocembrol under the action of HCOOH + D2O the D atom enters position 7α of the product molecules exclusively, which is in harmony with the proposed cyclization scheme. Using model compounds, an alternative scheme for the formation of one of the products has been disproved.