title: Heterobimetallic metallation studies of N,N-dimethylphenylethylamine (DMPEA): benzylic C-H bond cleavage/dimethylamino capture or intact DMPEA complex.
abstract: Reaction of the sodium monoamido-bisalkylzincate [(TMEDA)Na(TMP)(Bu(t))Zn(Bu(t))] (TMEDA is N,N,N',N'-tetramethylethylenediamine; TMP is 2,2,6,6-tetramethylpiperidide) and the related lithium zincate [(PMDETA)Li(TMP)Zn(Bu(t))2] (PMDETA is N,N,N',N'',N''-pentamethyldiethylenetriamine) with the sensitive bio-relevant scaffold N,N-dimethylphenylethylamine, DMPEA, afforded the crystalline complexes [(TMEDA)Na(TMP)(NMe2)Zn(Bu(t))] and [(PMDETA)Li(NMe2)Zn(Bu(t))2], respectively, both of which have been characterized by NMR spectroscopic and X-ray crystallographic studies. Made by reaction of a LiTMP-(TMP)Al(Bu(i))2 mixture with DMPEA, a third dimethylamino-containing crystalline complex, the aluminate [(THF)Li(TMP)(NMe2)Al(Bu(i))2] has been similarly characterized. All three complexes can be regarded as products of cleave and capture chemistry whereby metallation at the benzylic position of DMPEA has led to a β-elimination of an anionic Me2N fragment that has been captured by a charge balancing cationic heterobimetallic entity. While a metallated intermediate prior to the elimination has proved elusive in all of these reactions, DMPEA has been captured fully intact in the novel Lewis acid-Lewis base crystalline complex [DMPEA·Li(TMP)Zn(Me)2], which has also been characterized by the aforementioned techniques.
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK. r.e.mulvey@strath.ac.uk.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kennedy
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mulvey
authors.forename: Donna L
authors.initials: DL
authors.lastname: Ramsay
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Robertson