Green–Davies–Mingos rules
In organometallic chemistry, the Green–Davies–Mingos rules predict the regiochemistry for nucleophilic addition to 18-electron metal complexes containing multiple unsaturated ligands.[1] In general, complexation enhances the susceptibility of unsaturated hydrocarbon toward nucleophilic attack.
- Rule 1. Nucleophilic attack is preferred on even-numbered polyenes (even hapticity).
- Rule 2. Nucleophiles preferentially add to acyclic polyenes rather than cyclic polyenes.
- Rule 3A. Nucleophiles preferentially add to even-hapticity polyene ligands at a terminal position.
- Rule 3B. Nucleophiles add to odd-hapticity acyclic polyene ligands at a terminal position if the metal is highly electrophilic, otherwise they add at an internal site.
References
- ^ Stephen G. Davies et al (1977). "Nucleophilic Addition to Organotransition Metal Cations Containing Unsaturated Hydrocarbon Ligands". Tetrahedron 34: 3047–3077. doi:10.1016/0040-4020(78)87001-X.