Generation of bis(pentafluorophenyl)borane–dimethyl sulfide complex as a solution of hexane and its application to hydroboration of alk-1-yne with pinacolborane

A Combined DFT/IM-MS Study on the Reaction Mechanism of Cationic Ru(II)-Catalyzed Hydroboration of Alkynes

“…It is well-known that transition metal-catalyzed hydroboration of terminal alkynes proceeds regio- and stereoselectively. The reaction generally is anti -Markovnikov and involves cis -addition. , The generally accepted mechanism for the cis -hydroboration reaction involves oxidative addition of a B–H bond to the metal center, followed by alkyne insertion, generating a metal σ-vinyl intermediate and subsequent reductive elimination (Scheme (a)) . Hydroboration of internal alkynes also involves cis -addition and forms Z -alkenyl-boronates. ,, However, the general trans -selectivity of hydroboration has remained a very challenging problem and is one of the obscure details of organoboron chemistry.…”

The Thioether–Methyleneborane (PhSCH2B(C6F5)2)2: Synthesis and Reactivity with Donors and Alkynes

“…In FLP chemistry, sulfur-based donors have drawn less attention, although the adduct B(C 6 F 5 ) 3 ·SMe 2 in combination with a bulky phosphine has been shown to effect the heterolytic cleavage of H 2 . Similarly, thioethers such as Me 2 S and (PhCH 2 ) 2 S have been shown to add to terminal alkynes in the presence of B(C 6 F 5 ) 3 to yield trans- zwitterions of the form R 2 SC(R′)CH(B(C 6 F 5 ) 3 ) (Scheme ). , It is also noteworthy that the lability of thioether donors has been exploited by Hoshi et al in the reaction of B(C 6 F 5 ) 3 with BH 3 ·SMe 2 to generate the adduct of Piers’ borane (C 6 F 5 ) 2 BH·SMe 2 , , which was subsequently used in a catalytic fashion for the hydroboration of a terminal alkyne with HB(pin). The weak interaction between B and S has also been employed by Gabbaï and co-workers in the development of aryl-linked boron–sulfur sensors for cyanide and fluoride ions in water. , Methylene-linked thioether boranes are rare.…”

The Preparation of Complexes of Germanone from a Germanium μ‐Oxo Dimer

“…In the 1 HNMR spectrum of compound 2,t he resonance signals for the methyl protons of the iso-butyl and iso-propyl groups appeared as two doublets (d = 0.98, 1.30 ppm) and one doublet (d = 0.78 ppm), respectively.S ignals for the methine protons of the iso-butyl and iso-propyl groups were seen as am ultiplet in the range of d = 2.06-2.15 and 0.94-1.04 ppm, respectively.The diastereotopic methylene protons of the isobutyl groups resonated as two double doublets (d = 2.89 and 3.00 ppm). [9] Similarly,through an examination of the 19 FNMR spectra, significant differences are evident in the chemical shifts of the signals for the fluorine atoms in compound 5 (d = À134, À161, and À166 ppm) and B(C 6 F 5 ) 3 (d = À128, À143, and À160 ppm). Compound 3 showed as imilar splitting pattern for the iso-butyl and isopropyl protons except the methylene protons which appear as am ultiplet (d = 3.63-3.78 ppm).…”

“…Thefree Lewis acid B(C 6 F 5 ) 3 showed aresonance signal at d = À2.3 ppm. [9] Similarly,through an examination of the 19 FNMR spectra, significant differences are evident in the chemical shifts of the signals for the fluorine atoms in compound 5 (d = À134, À161, and À166 ppm) and B(C 6 F 5 ) 3 (d = À128, À143, and À160 ppm). [10] Additional evidence for the stability of complexes of germanone in solution was obtained through 1 HD OSY NMR experiments on compounds 4-5 (see Figure S2 for arepresentative example).…”