What is the starting point for a constructive trust claim?

In any claim for constructive trust involving a common law relationship the starting point is Pettkus v. Becker, 1980 CanLII 22 (SCC), [1980] 2 S.C.R. 834, in which Dickson J., set out the three requirements needed to establish unjust enrichment, the principle lying at the heart of the constructive trust: an enrichment, a corresponding deprivation, and the absence of any juristic reason for the enrichment (at p. 848). At p. 852, he noted that there must be a link between the contribution that founds the action and the property in which the constructive trust is claimed.