... DOI: 10.1039/C0DT01502D (Paper) Dalton Trans., 2011, 40, 3748-3753 Show Compounds Show Chemical Terms. ... 4a,4b,5,14 By changing the ratio of 2 : 3a to 1 : 2.5, the homocyclo-trimerization of 2 was almost completely suppressed resulting in a 92% yield of 4a. ...