Sulfur doxide insertion. XV. Transition metal-vinyl complexes containing a sultine ring

Unprecedented Spectroscopic and Computational Evidence for Allenyl and Propargyl Titanocene(IV) Complexes: Electrophilic Quenching of Their Metallotropic Equilibrium

“…These results are in agreement with those previously reported for 1-chloro-3-(trimethylsilyl)propargyl and -allenyl titaniumd erivatives, which also showed that these species are configurationally stable at temperatures below À40 8C. [15] There can, of course, be ac ombination of both thermodynamic and kinetic factors that contribute to the ratio of the products,d epending on the relative rates of these processes. [38] However, low temperatures produced full pinacolization of the carbonyl substrates, precluding the evaluation of such experimentalc onditions.…”

“…[16] These authors postulate the existence of the metallotropic equilibrium between propargyl and allenylc omplexes, showing their configurational stability at certain conditions, but unfortunately attempts to characterize the metallocarbenoids by low-temperature NMR experimentsw ere unsuccessful. [15] In this case, the reactive intermediate proved to react in both its propargylic and allenic forms, affording mixtures of a-allenic and b-acetylenic alcohols with modest regioselectivities.…”

“…On the other hand, Chemla andF erreira have compared the stabilities of titanium carbenoids with the corresponding lithium and zinc derivatives. [15] As in the synthesis of complex 1,the corresponding titanium organometallics werep reparedb yl ithiation with nBuLi at À95 8Ci nt he presence of tetramethylethylenediamine (TMEDA) and subsequentt ransmetallation with Ti(iPrO) 4 . [16] These authors postulate the existence of the metallotropic equilibrium between propargyl and allenylc omplexes, showing their configurational stability at certain conditions, but unfortunately attempts to characterize the metallocarbenoids by low-temperature NMR experimentsw ere unsuccessful.…”

“…Keywords: density functional calculations · DOSY · metallotropic equilibrium · NMR spectroscopy · titanocenes [16] As pointed out by one of the reviewers, it is worth mentioning that the Ti III /propargyl combinationr eported herein is am orec onvenient way of preparing allenyl Ti IV complexes than previous procedures such as those described by Chemla and Ferrerira in reference [15]. …”

Reactions of Tungsten Propargyl and Allenyl Complexes with Hydrido Triosmium Cluster: Molecular and Crystal Structure of Cp(CO)2[P(OMe)3]W(μ, η1, η2‐CH2CH=CH)OS3(CO)10H and H2(CH2CH = CH)2Os6(CO)20

“…In contrast, the coordination of the carbon atom in 4a (10) 0.05050 (1) 2.37(6) 052 0.26792 (11) 0.61790 (11) 0.14690 (7) 2.65 (7) C3H4)OS3(CO)10H OS3 0.43515 (10) 0.73823 (12) 0.lm5 (8) 3.06 (7) Os (2)-Os(1)-Os (3) 59.88 (6) Os (1)-Os(3)-Os (2) 59.00 (1) OS4 0.18718 (11) 0.29289 (11) -0.15136 (7) 2.71 (1) 0s(2)·0s(1)-C (1) 116.1 (9) Os(1)-Os(3)·C (7) 160-4(13) OS5 0.281&4(10) 0.25617 (11) .0.00925 (7) 2.41 (6) OS(l)·Os(1)-C(2) 130.9 (9) Os(I)·Os (3)·C (8) 83.9(11) OS6 0.10162 (11) 0.16072 (12) -0.07186 (8) 3.13 (1) Os (2) (17) 2.5 (7) Os (3)-Os(1)-C (1) 172.6(9) Os (2) (17) 24 (7) Os (3)-Os(1).C (2) 81.0(9} Os (2) (9) Os{3)-0s(1)-C{19) 113.3 (7) C (7)-Os (3) (8) Os (3)·Os (1) (3) O.676{4) 0.2602(24) 6.2...…”