53213-06-2Relevant articles and documents
Combined rhodium-catalyzed carbon-hydrogen activation and β-carbon elimination to access eight-membered rings
Crepin, Damien,Dawick, James,Aissa, Lhnstopne
supporting information; experimental part, p. 620 - 623 (2010/04/05)
(Figure Presented) Enlargel C-H bond activation and β-carbon elimination are combined in a net intramolecular hydroacylation of alkylidenecyclobutanes and alkylideneazetidines in the presence of rhodium catalysts, affording eight-membered-ring compounds in high yield (see scheme). This study demonstrates the possibility of exploiting the strain energy of azetidines through β-carbon elimination in new transition-metal-catalyzed reactions.
Strain-Activated 1,3-Butadienes. Synthesis and Dienic Reactivity of Dicyclobutylideneethane
Wickham, Geoffrey,Wells, Gregory J.,Waykole, Liladhar,Paquette, Leo A.
, p. 3485 - 3489 (2007/10/02)
A synthesis of dicyclobutylideneethane (3) is described.An approach involving 1-(trimethylsilyl)-substituted cyclobutanes was first examined and shown not to be conducive for gaining access to this strained diene.A Wittig approach involving condensation of cyclobutylideneacetaldehyde (18) with cyclobutylidenetriphenylphosphorane (20) did deliver 3, whose dienic behavior toward several dienophiles was examined.The electronic spectrum of 3 resembles that of the bicyclohexylidene analogue and its relative reactivity in a representative Diels-Alder reaction was shown to be lower than that of 1.Despite the obvious steric congestion at its bonding centers, however, 3 has reasonable reactivity.Various approaches to cyclobutylidenecyclopropylideneethane (2) have been examined without success.These efforts are briefly summarized.
