4 research outputs found
Tandem Synthesis of Linear Hydridopolycarbosilanes and Postfunctionalization by a Calcium Catalyst
No full textRecent
years have witnessed great progress in the application of
calcium-based catalysts in a variety of organic transformations, including
hydrofuctionalization, dehydrogenative coupling, and C–H activation.
However, these efficient protocols in polymer synthesis remain much
less explored. Here, we report the selective bis-hydrosilylation of
dienes with bis-hydrosilanes in the presence of scorpionate-supported
calcium benzyl complex [(TpAd,iPr)Ca(p-CH2–C6H4-Me)(THP)]
(TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate,
THP = tetrahydropyran) (1) to obtain linear polycarbosilanes
containing a reactive SiH2 unit in the main chain. Furthermore,
complex 1 can also catalyze the dehydrogenative silylation
of terminal alkyne, silylamination of aniline, and C–H activation
of 1-methyl-1H-indole, with the Si–H bonds
in polycarbosilanes to allow the introduction of 35–65% new
side chains in these polymers. The resulting new polymers contain
unusual units including SiH–(CCPh), SiH–(NHAr),
and SiH–(indole), whose presence is confirmed by NMR and IR
spectra
Regioselective C–H Alkylation of Aromatic Ethers with Alkenes by a Half-Sandwich Calcium Catalyst
No full textThe
catalytic ortho-regioselective C–H
alkylation of a variety of alkoxy-substituted benzene derivatives
with alkenes can be achieved by the use of a half-sandwich calcium
alkyl complex [(CpAr5)Ca{CH(SiMe3)2}(THF)] (2) (CpAr5 = C5Ar5, Ar = 3,5-iPr-C6H3) as the precatalyst. The potential catalytic reaction intermediates,
half-sandwich calcium anisyl complexes [(CpAr5)Ca(o-MeO-m-Ph-C6H3)
(THF)2] (8) and [(CpAr5)Ca(o-MeO-2-Np) (THF)2] (9) (Np = naphthyl),
were isolated and X-ray structurally characterized. DFT calculations
were carried out to elucidate the different reaction profiles of sp2 and sp3 C–H activations
Regioselective C–H Alkylation of Aromatic Ethers with Alkenes by a Half-Sandwich Calcium Catalyst
No full textThe
catalytic ortho-regioselective C–H
alkylation of a variety of alkoxy-substituted benzene derivatives
with alkenes can be achieved by the use of a half-sandwich calcium
alkyl complex [(CpAr5)Ca{CH(SiMe3)2}(THF)] (2) (CpAr5 = C5Ar5, Ar = 3,5-iPr-C6H3) as the precatalyst. The potential catalytic reaction intermediates,
half-sandwich calcium anisyl complexes [(CpAr5)Ca(o-MeO-m-Ph-C6H3)
(THF)2] (8) and [(CpAr5)Ca(o-MeO-2-Np) (THF)2] (9) (Np = naphthyl),
were isolated and X-ray structurally characterized. DFT calculations
were carried out to elucidate the different reaction profiles of sp2 and sp3 C–H activations
Regioselective C–H Alkylation of Aromatic Ethers with Alkenes by a Half-Sandwich Calcium Catalyst
No full textThe
catalytic ortho-regioselective C–H
alkylation of a variety of alkoxy-substituted benzene derivatives
with alkenes can be achieved by the use of a half-sandwich calcium
alkyl complex [(CpAr5)Ca{CH(SiMe3)2}(THF)] (2) (CpAr5 = C5Ar5, Ar = 3,5-iPr-C6H3) as the precatalyst. The potential catalytic reaction intermediates,
half-sandwich calcium anisyl complexes [(CpAr5)Ca(o-MeO-m-Ph-C6H3)
(THF)2] (8) and [(CpAr5)Ca(o-MeO-2-Np) (THF)2] (9) (Np = naphthyl),
were isolated and X-ray structurally characterized. DFT calculations
were carried out to elucidate the different reaction profiles of sp2 and sp3 C–H activations
