title: Pd-catalysed reactions of alkynes with model distannanes and poly[di-(n-butyl)]stannane.
abstract: A reinvestigation of Pd-catalysed alkyne (R'-C≡CH; R' = H, Ph) insertion chemistry involving R(3)SnSnR(3) (3a: R = Me; 3b: R = n-Bu) was undertaken. Model distannyl ethylenes 4a-b (Me(3)SnCH=CR'SnMe(3)) and 5a-b ((n-Bu)(3)SnCH=CR'Sn(n-Bu)(3)) were reproduced and further characterized by NMR ((119)Sn, (13)C, (1)H) and UV-Vis spectroscopy. In the presence of an excess of phenylacetylene, dimerization-carbostannylation of compound 4b yielded the new conjugated butadiene, (Z,Z)-1,4-bis(trimethylstannyl)-1,4-diphenyl-buta-1,3-diene (9). An X-ray structure determination of 9 reveals a symmetrical double-bond Z confirmation. Compound 9 was further characterized by NMR, UV-Vis spectroscopy, and MS. A DFT analysis of model compounds (4a-b, 5a-b, 9) and the experimental and theoretical λ(max) values from the UV-Vis spectra were also compared. Acetylene and phenylacetylene Pd-catalysed insertion into the backbone of poly[di-(n-butyl)]stannane 12 resulted in new, modest molecular weight, partially inserted alkene tin polymers (13a-b) that were also characterized by GPC, NMR, UV-Vis spectroscopy and elemental analysis.
authors.affiliation: Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ontario, Canada M5B-2K3.
authors.forename: Aman
authors.initials: A
authors.lastname: Khan
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Lough
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gossage
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Foucher
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D008958:Models, Molecular; D015394:Molecular Structure; D009947:Organotin Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011789:Quantum Theory; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D000480:Alkynes; D009947:Organotin Compounds; D017971:Tin Compounds; C056189:di-n-butyltin; C031525:stannane; D010165:Palladium