Cyclobutenes as isolable intermediates in the gold(I)-catalysed cycloisomerisation of 1,8-enynes
Abstract
The gold(I)-catalysed isomerisation of 1,8-enynes allows the efficient synthesis of function -alised bicyclo[5.2.0]nonenes. Notably, these cyclobutenes derivatives can be isolated as reactive intermediates that could undergo subsequent gold(I)-catalysed transformations such as isomerisation, fragmentation or ene reaction to furnish more structurally complex products. This study also provides useful information related to the mechanism leading to metathesis-type derivatives, examples of which were shown to be produced, in the present case, by a gold(I)-catalysed ring fragmentation of the cyclobutene moiety. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.