In Sharp v. Kosmalski, 40 N.Y.2d 119, 123, 351 N.E.2d 721, 386 N.Y.S.2d 72 (1976), the Court of Appeals set forth four elements to establish a constructive trust: "(1) a confidential or fiduciary relation; (2), a promise; (3) a transfer in reliance thereon; (4) unjust enrichment." There are no rigid requirements for the establishment of a constructive trust, and these are more aptly considered as guidelines. Because the fundamental purpose is to prevent unjust enrichment, a constructive trust is appropriate whenever necessary to satisfy the demands of justice. (Matter of Estate of Knappen, 237 A.D.2d 677, 655 N.Y.S.2d 110 [3d Dept 1997]).