Syntheses of gyroscope-like molecules via three-fold ring closing metatheses of bis(phosphine) complexes trans-LyM(P((CH2)nCHCH2)3)2, and extensions to bis(phosphite) complexes trans-Fe(CO)3(P(O(CH2)nCHCH2)3)2

Site-specific PEGylation of proteins by a Staudinger-phosphite reaction

“…A similar trend was observed during the conversion of peptide 1 into phosphoramidate 5 in the presence of tris(tetraethylene glycol) phosphite (4), which was prepared according to the procedure adapted from the literature (Table 1, entries 4-7). 47 Since phosphites are known to rearrange to phosphonates at low pH in aqueous media, 48,49 we proposed that the observed efficiencies of the peptide modification might be associated with the decomposition of phosphites 2 and 4 in the reaction mixtures. In order to evaluate this hypothesis, we monitored the decay of these phosphites in aqueous buffers by 31 P-NMR.…”

“…39 It is important to note that, similarly to 4, phosphite 15 can be easily prepared in one step from inexpensive commercially available reagents. 47 Given the fact that mPEG-OH polymers of various molecular weights are readily available, this method could be potentially used for the preparation of other homologues of 15.…”

Gyroscope like molecules consisting of trigonal or square planar osmium rotators within three-spoked dibridgehead diphosphine stators: syntheses, substitution reactions, structures, and dynamic properties

“…As shown in Scheme 1, we have discovered that three fold intramolecular and interligand ring closing alkene metatheses of trans bis( phosphine) complexes of the type I can be effected in surprisingly high yields. [7][8][9][10][11][12] This methodology has been used to access square planar, trigonal bipyramidal, and octahedral complexes, as detailed in earlier reports. Since mixtures of Z/E CvC isomers are commonly obtained, hydrogenations are subsequently effected, giving homogeneous samples featuring cage like trans spanning dibridgehead diphosphines that encapsulate the remaining ligands (II).…”

Substitution and Catalytic Chemistry of Gyroscope‐Like Complexes Derived from Cl–Rh–CO Rotators and Triply trans Spanning Di(trialkylphosphine) Ligands

“…The central metal can bear two, three, or four ancillary ligands (L y ), corresponding to square planar, trigonal bipyramidal, and octahedral coordination geometries, respectively. When these ligands are sufficiently small, rotation of the ML y moiety or “rotator” about the P–M–P axis is rapid on the NMR time scale 4–9. Substitution reactions can often be effected within these cages,4–8 and the replacement of smaller ligands by larger ligands can serve to “brake” rotation 5–8…”