An efficient synthesis has been realized for several members of a new class of potential boneresorption inhibitors consisting of steroidal oestrogenic units linked at the 3 and 17 positions to ageminal bisphosphonate moiety through an ester linkage of variable length. The convergentsynthesis utilizes benzyl bisphosphonates, transesterification, and Meldrum's acid chemistry andhas the potential to allow many oestrogenic derivatives as well as other biologically active compoundsto be coupled to the geminal bisphosphonate moeity.