Stereoselectivity in the complexing of platinum(II) chloride with substituted cyclopropanes

Abstract

minor signals may represent lg5Pt satellites ; vicinal lg5Pt-H coupling is clearly observed in related acyclic analogue^.^,^

The stereochemistry of addition of cyclopropanes to tetrachloro(diethylene)platinum(II)

“…Coupling of the trat~s-2,3-hydrogens with H I was 7.5 Hz and with I9jPt it was 82 HZ. The above assignments are consistent with the shielding and couplings observed in other three (24) and four (25) membered rings and previously reported for 8 (23).…”

“…In the present case the process may be rationalized as involving interaction of the lowest Walsh (35,36) orbital of the cyclopropane with a vacant orbital on platinum (37). Such a view is consistent with the increase in reactivity of cyclopropanes with 2 upon substitution of the former with electron donating groups (23).…”

“…The insoluble yellow adducts thus formed were reacted with pyridine l o give the corresponding bispyridine adducts (23). These adducts were then analyzed by 220 MHz nmr to determine the stereochemistry of the insertion reaction.…”

“…It was anticipated that the distinction between these three possibilities would be evident upon examination of the chemical shifts (23) and vicinal coupling (24,25) of M, and FI, in 3 and 4…”

“…Insertion of the Pt" complex 2 into substituted cyclopropanes has been investigated by several groups (15)(16)(17)(18)(19)(20)(21)(22)(23). In this case the reaction led to the formation of polymeric (16) The present investigation was undertaken to determine the stereochemistry of the addition of 2 to the strained C-C bonds of substituted cyclopropanes, Mnowiedge of the stereochemisirp of this addition process is crucial to the understanding of the mechanism of this and related oxidative addition reactions.…”