In this study, a series of 2', 4-' or 3', 4'-doubly branched carbocyclic nucleosides (11, 12, 19, and 20) were synthesized from simple acyclic ketone derivatives as starting materials. The installation of the 4'-quaternary carbon needed was carried out using a [3, 3]-sigmatropic rearrangement. In addition, the introduction of a methyl group in the 2'- or 3'-position was accomplished by either Grignard reaction or Horner-Wadsworth-Emmons reaction with triethyl-2-phosphonopropionate, respectively. Bis-vinyl was successfully cyclized using a Grubbs' catalyst II. The natural bases (adenine, cytosine) were coupled efficiently using a Pd(0) catalyst. Although all the synthesized compounds were assayed against several viruses, only the cytosine analogue showed moderate antiviral activity against the human cytomegalovirus.