Tetrathioorthocarbonate as a C4+ Synthon. Nickel-catalysed Alkylative Alkenation of Tetrathioorthocarbonate with Grignard Reagents
The nickel-catalysed cross-coupling reactions of tetrathioorthocarbonate 1 with Grignard reagents give the corresponding substituted alkenes in moderate to good yields; the reaction demonstrates the first example of using tetrathioorthocarbonate as a C4+ synthon.
Trithioorthoesters and Tetrathioorthocarbonates as RC(3+) and C(4+) Synthons. Nickel-Catalyzed Alkylative Olefination of Trithioorthoesters and Tetrathioorthocarbonates
NiCl2(PPh3)2-catalyzed alkylative olefinations of trithioorthoesters and tetrathioorthocarbonates give the corresponding substituted alkenes.Aliphatic C-S bonds in these substrates can be activated in the nickel-catalyzed cross coupling reaction leading to carbon-carbon bond formation.This reaction can be considered as using trithiorthoesters and tetrathioorthocarbonate as R3C(3+) and C(4+) synthons. - Keywords: Trithioorthoesters, Tetrathioorthocarbonate, Nickel-Catalyzed Alkylative Olefination, Synthons of RC(3+) and C(4+)
Tzeng, Yih-Ling,Cheng, Wen-Lung,Luh, Tien-Yau
p. 385 - 393
(2007/10/02)
MARKED EFFECTS OF RING SIZE ON THE CORRELATED ROTATION OF THE CYCLOALKYL GROUPS OF 1,1-DICYCLOALKYLMETHYLENECYCLOALKANES
Correlated rotation of the cycloalkyl groups has been observed by 13C NMR for the title compounds containing six-, seven-, or eight-membered rings.The ΔH(excit.) value increases with the increase in the ring size, attaining 79.5 +/- 2.1 kJ mol-1 when all the three rings are eight-membered.Molecular mechanics calculations indicated that the magnitude of internal angles is a major contributing factor.