2-(Trimethylsilyloxy)furan as a dianion equivalent: a two-step synthesis of functionalized spirocyclic butenolides.
[reaction: see text] The use of 2-(trimethylsilyloxy)furan derivatives as dianion equivalents leads to a general and connective spiroannulation protocol for the efficient preparation of spirocyclic butenolides.
Efficient synthesis of spirolactones from cyclic anhydrides via an allylation/alkylation-RCM sequence
Abstract Starting from cyclic anhydrides the diallyl or dibutenyl lactones were obtained. The ring closing metathesis reaction of these using the Grubbs catalyst provided the corresponding spirolactones in good yields. With diallyl δ-lactone 2h , RCM occurred only in the presence of titanium tetraisopropoxide.
Fasciculatin, a novel sesterterpene from the sponge Ircinia fasciculata
Abstract A new furanosesterterpene, fasciculatin, has been isolated from the sponge Ircinia fasciculata . On the basis of physical and chemical evidence structure I is suggested for fasciculatin.