The epoxides derived from 5H-dibenzo[a.d]cycloheptene and its 2-fluoro derivative were converted to trans-fused hydrofurans 4a.b (55 and 44% overall fields) via a five-step sequence. i.e. (i) epoxide ring opening using propargylmagnesium bromide. (ii) mercury(II)-induced cyclisation and in situ bromination to give the bromomethylene substituted hydrofurans, (iii, iv) acid catalysed hydration and stereoselective reduction of the hemiacetal intermediates, and (v) base promoted cyclisation. (C) 2002 Elsevier Science Ltd. All rights reserved.