- Stereo- And regio-selective synthesis of silicon-containing diborylalkenes: via platinum-catalyzed mono-lateral diboration of dialkynylsilanes
-
A highly chemoselective platinum-catalyzed mono-lateral diboration of dialkynylsilanes for the construction of silicon-tethered alkynyl diborylalkenes is described, in which tris(4-methoxyphenyl)phosphine was found to be an effective ligand for the cis-addition of diboron agents to the silicon-tethered alkynes, and the chiral ligand (AFSi-Phos)-mediated diboration of dialkynylsilanes resulted in the desymmetric construction of silicon-stereogenic centers with promising enantioselectivity.
- Long, Peng-Wei,Xie, Jia-Le,Yang, Jing-Jing,Lu, Si-Qi,Xu, Zheng,Ye, Fei,Xu, Li-Wen
-
supporting information
p. 4188 - 4191
(2020/04/22)
-
- Quantitative substituent effects in the Grignard reaction with silanes
-
Kinetics of reactions of ethyl- and phenylmagnesium chlorides with chlorosilanes, RMeSiCl2, were investigated in diethyl ether under pseudo-first order conditions with a great excess of the Grignard reagent. Rate constants for alkyl substituted silanes correlate well with Es(Si) steric parameters. A good linear correlation of rate data for substituted phenyl derivates with σ0 inductive constants together with correlations of the literature data rule out the resonance effect of substituents at least in nucleophilic displacement reactions at the silicon center. An attempt to calculate the steric constants for polar substituents was made. It appeared that the inductive constants σ* derived from the carbon chemistry are not applicable to the silicon chemistry. New scales of parameters for description of polar and steric effects in the organosilicon chemistry need to be created.
- Golubev, Oleg,Panov, Dmitri,Ploom, Anu,Tuulmets, Ants,Nguyen, Binh T.
-
p. 3700 - 3705
(2008/02/08)
-
- Macrocyclic polyether compounds
-
Macrocyclic polyether "crown" compounds of the formula EQU1 WHEREIN T is a C2 -C3 alkylene, A is EQU2 R being H or C1 -C18 alkyl, R2 and R3 being independently C1 -C18 alkyl, C2 -C4 alkenyl, or C6 -C14 aryl; Q and Z are independently 1,2-arylene (or saturated derivatives thereof) or substituted 1,2-arylene (or saturated derivatives thereof); a is 0, 1, 2, or 3; b is an integer from 3 to 20; y is 1 or zero; x1, x2, x3, and x4 are integers independently selected to give a 15-60 atom ring. Such crown compounds are generally useful in the formation of complexes with ionic metal compounds, thus making it possible to use certain chemical reagents in media wherein they are normally insoluble.
- -
-
-