Synthesis of [4.6.4.6]fenestradienes and [4.6.4.6]fenestrenes based on an 8pi-6pi-cyclization-oxidation cascade.
Fenestranes are regarded as a particularly challenging synthetic targets, and only few syntheses have been reported in the recent past. These rare compounds of synthetic and theoretical interest are a class of tetracyclic skeletons, defined as doubly a,a'-bridged spiroalkanes. The reported results are focused on the synthesis of new and original [4.6.4.6]fenestradienes 3a-f and [4.6.4.6]fenestrenes 4a-e. Our approach implies the formation of this tetracyclic structure by a reaction cascade, based on consecutive transformations starting from the trienyne 1a-f: an initial soft hydrogenation using a P-2 Nickel catalyst at room temperature, followed by a conrotatory 8p electrocyclization and a disrotatory 6p electrocyclization and a final oxidation. Several examples of this type of new compounds are described in this Communication.
Hulot
Catherine
C
Faculté de Pharmacie, Université Louis Pasteur de Strasbourg, (LC01 UMR 7175 CNRS/ULP), 74 Route du Rhin, 67401 Illkirch/Strasbourg, France.
Blond
Gaëlle
G
Suffert
Jean
J
D018360:Crystallography, X-Ray; D003500:Cyclization; D006589:Hexestrol / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction
D006589:Hexestrol; C043879:phenestrol