A variety of nonsteroidal systems can function as ligands for the estrogen receptor (ER), in some cases showing selectivity for one of the two ER subtypes, ERα or ERβ. We have prepared a series of heterocycle-based (furans, thiophenes, and pyrroles) ligands for the estrogen receptor and assessed their behavior as ER ligands. An aldehyde enone conjugate addition approach and an enolate alkylation approach were developed to ...