The regio- and stereospecific synthesis of diarylpropenyllithium compounds from dimethylamino- and dimethylaminomethyl-substituted diarylacetylenes via transmetallation reactions involving diarylpropenylmagnesium and -tin compounds
article
Dimethylamino- and dimethylaminomethyl-substituted diarylacetylenes were prepared by the Pd(PPh3)4-catalyzed coupling reaction of dimethylamino- and dimethylaminomethyl-substituted aryl halides with arylacetylenes. Reaction of the asymmetric diarylacetylenes with methylmagnesium bromide in the presence of NiCl2(PPh3)2 gave stereo- and regio-selectively cis addition products in which the aryl group bearing the built-in ligand (Me2N or Me2NCH2) and the magnesium atom are bonded to the same unsaturated carbon atom. The E-diarylpropenylmagnesium bromides were converted in two successive transmetallation steps into the corresponding E-triphenyltin and Z-lithium compounds with retention of configuration. Depending on the type of solvent, complete inversion of configuration was observed for the Z-diarylpropenyllithium compounds. From the E-lithium compounds the corresponding Z-diarylpropenyltriphenyltin compounds were prepared (Scheme 1). Retention of configuration in the series of transmetallation reactions has unambiguously been established by comparison of the 119Sn1H, 13C1H and 119Sn13C coupling constants observed in the 1H and 13C NMR spectra of the configurationally pure stereoisomeric pairs. ?? 1979.
Topics
TNO Identifier
228664
ISSN
0022328X
Source
Journal of Organometallic Chemistry, 170(2), pp. 131-149.
Pages
131-149
Files
To receive the publication files, please send an e-mail request to TNO Repository.