A one-pot metathetic ring opening of substituted bicyclo[3.2.0]heptenones to linear polyene ketones is described. The reaction proceeds with conservation of the endocyclic (Z)-double bond. Exo-substituted vinylcyclobutanones result in (4Z,6E)-configured trienones, while endo-substituted phenyl derivatives generate (4Z,6Z)-configured dienones.
![Graphical abstract: An unprecedented stereoselective [2+2] cycloreversion of cyclobutanones](http://hg.y866.cn/compound/lib/scimg/usr/1/C0CC02694H.jpg)
