“…A viable access to a stable singlet derivative of formal heteroatomic cyclopentane-1,3-diyls was found in the 1,1-insertion of carbon monoxide, C O, into cyclodiphospha diazanediyl, [P(μ-NTer)] 2 ( 1PP ), which afforded species E ( Scheme 2 ). 44 Subsequent systematic investigations targeted the activation of isonitriles, C N–R (R = t Bu, Dmp, N(SiMe 3 ) 2 , Ter; Ter = 2,6-dimesityl-phenyl, Dmp = 2,6-dimethylphenyl), with diphosphadiazanediyl 1PP . By variation of the organic substituent, steric and electronic properties of the isonitrile could be varied.…”