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The first efficient and regioselective palladium-catalyzed cyclization of internal alkynes and 2-amino-3-iodoacrylates to give moderate to excellent yields of highly functionalized pyrroles has been developed. This approach is applicable to a range of alkynes and affords the deacylated pyrrole under reaction conditions for most substrates. [reaction: see text]

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Analogous to trifluoromethyltrimethylsilane (Ruppert’s reagent) (E)-trimethyl(perfluoroprop-1-enyl)silane (1), prepared by deprotonation of (Z)-1,2,3,3,3-pentafluoroprop-1-ene (2a) at −78 °C in the presence of chlorotrimethylsilane, was shown to transfer the perfluoroprop-1-enyl group to a number of electrophiles containing carbonyl group in the presence of catalytic amount of fluoride anion. The perfluoroprop-1-enyl group was transferred to formaldehyde, acetaldehyde, benzaldehyde, acetone, trifluoroacetophenone resulting in formation of corresponding TMS-ethers of secondary and tertiary alcohols containing Z-CF3CFCF– fragment. With some substrates such as hexafluoroacetone, formaldehyde, and trifluoroacetophenone, substituted 5-membered dioxolane products of the reaction can be obtained, depending on the reaction conditions and the source of fluoride catalyst.

The effectiveness of hetero-COSY, HETCOR, HMQC, and HSQC two-dimensional NMR pulse sequences for detection of (19)F-(1)H correlations by scalar coupling was evaluated on monofluorinated and polyfluorinated test compounds. All four of these sequences were effective in observing (1)H-(19)F correlations, using either (19) F or (1)H as the observe nucleus. All four sequences were amenable, to some degree, to adjustment to observe larger or smaller couplings preferentially. A 1/2J echo filter was effectively applied to remove artifacts from (2)JFF strong coupling. The HETCOR experiments afforded the best overall combination of sensitivity, resolution and selectivity for JHF.