α-oxo-acetals (3b, 5b, 17, 18) through an enolization/ionization mechanism. With trifluoroethanol/sodium trifluoroethoxide, the corresponding trifluoroethyl acetals (3a and 5a) are formed. Basic hydrolysis affords 2-endo-hydroxynorbornene-2-exo-carboxylic acid (20x) and the 7-oxa analogues (22x, 23x), presumably through benzilicacidrearrangement of the α-diketones.
Convergent Assembly of the Tricyclic Labdane Core Enables Synthesis of Diverse Forskolin‐like Molecules
作者:Paweł M. Szczepanik、Andrey A. Mikhaylov、Ondřej Hylse、Roman Kučera、Petra Daďová、Marek Nečas、Lukáš Kubala、Kamil Paruch、Jakub Švenda
DOI:10.1002/anie.202213183
日期:2023.1.2
large family of bioactive naturalproducts. Their often-complex structures present challenges to semisynthesis and denovo chemical synthesis in search of analogs with improved properties. To enable new modifications of the well-known tricyclic terpene forskolin, we have developed a distinct and potentially general synthetic scheme for the preparation of analogs of complex labdanes.