Preparation of some ketoorganostannanes and ketoorganochlorostannanes. Intramolecular coordination in ketoorganochlorostannanes

Synthesis of a Lewis acid bearing cyclopentadienyl ligand and its tricarbonylmanganese(I) complex

“…A similar Lewis acid-base interaction has been observed for the aforementioned ketoorganochlorostannanes ( Fig. 1) as demonstrated by an approximately 30 cm À1 shift of the CO stretching frequency to lower energy for the ketoorganochlorostannanes vs. the corresponding ketoorganostannanes [10]. However, for the case of 1 and 2, prepared herein, the CO stretching frequencies overlapped almost exactly (1943 and 2024 cm À1 for 1 and 1944 and 2025 cm À1 for 2).…”

“…Though CPK models and simple molecular mechanics calculations (Spartan) demonstrated that a three carbon spacer should allow interaction between the Lewis acidic Sn moiety and the carbonyl oxygen without undue strain, our result does not preclude the possibility of interaction in analogous complexes with different separation between the LA and the TM. It is also likely that the Lewis acidity of the organochlorostannane is insufficient to bind to the CO ligand which is presumably less basic than the ketone oxygen in the Kuivila precedent [10,13].…”

“…Our goal is to devise a scheme whereby a Lewis acid is covalently tethered, via a variable length linkage, to a TM binding site. We have chosen chloroalkylstannanes as the Lewis acid moiety due to the versatility of organostannane chemistry [9] and because of the ability of tethered organochlorostannanes to act as Lewis acids as demonstrated by Kuivila et al [10] with ketoorganochlorostannanes ( Fig. 1).…”

Photochemistry of ketoalkyltrimethylstannanes in alkanes and in carbon tetrachloride

“…The preparations of 3-oxobutyltrimethylstannane and of 4-oxopentyltrimethylstannane were effected by methods previously described. 7 5-Oxohexyltrimethyltin was prepared by photochemically induced hydrostannation of 5-hexen-2-ol, with trimethyltin hydride, followed by Jones oxidation of the adduct to the ketone (eq 1).…”

“…K* + CCL, [K-CC1J* K" + Cl• + -CCL (7) Subsequent reactions then follow from the chlorine and trichloromethyl radicals. If this primary reaction occurs with our ketoorganostannanes, it is easy to account for the high yields of trimethyltin chloride, for the chlorine atoms formed in reaction could react with the stannyl function by an SH2 process (eq 8).…”