Facile cycloreversion of octacarbonyl-1,2-diosmacyclobutane: Convenient source of the Os2(CO)8 unit in the formation of 1,2-diosmacyclobutenes

Article abstract of DOI:10.1021/om00016a052

Cycloreversion of octacarbonyl-1,2-diosmacyclobutane, Os₂(CO)₈(μ-η¹:η¹-CH ₂CH₂) (1), can be affected by mild thermal (T > 28°C) or photochemical (λ > 330 nm) activation. In the presence of activated alkynes the reaction affords 1,2-diosmacyclobutenes in moderate to good yields, Os₂(CO)₈(μ-η¹:η ¹-RCCR′) (R = R′ = CO₂Me (2a), Ph (2b); R = H, R′ = CO₂Me (2c), C(O)Me (2d)). Compounds 2 have been characterized by IR and NMR spectroscopies. The ¹³C NMR spectra indicate that the molecules are static at room temperature with regard to CO exchange processes. A detailed preparation of 1 is reported as well.