Abstract
Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane is described. The hydrosilylation of alkenes using dimethyl(2-pyridyl)silane (2-PyMe2SiH) proceeded well in the presence of a catalytic amount of RhCl(PPh3)3 with virtually complete regioselectivity. By taking advantage of the phase tag property of the 2-PyMe2Si group, hydrosilylation products were isolated in greater than 95% purity by simple acid-base extraction. Strategic catalyst recovery was also demonstrated. The hydrosilylation of alkynes using 2-PyMe2SiH proceeded with a Pt(CH2= CHSiMe2)2O/P(t-Bu)3 catalyst to give alkenyldimethyl(2-pyridyl)silanes in good yield with high regioselectivity. A reactivity comparison of 2-PyMe2SiH with other related hydrosilanes (3-PyMe2SiH, 4-PyMe2SiH, and PhMe2SiH) was also performed. In the rhodium-catalyzed reaction, the reactivity order of hydrosilane was 2-PyMe2SiH ≫ 3-PyMe2SiH, 4-PyMe2SiH, PhMe2SiH, indicating a huge rate acceleration with 2-PyMe2SiH. In the platinum-catalyzed reaction, the reactivity order of hydrosilane was PhMe2SiH, 3-PyMe2SiH ≫ 4-PyMe2SiH > 2-PyMe2SiH, indicating a rate deceleration with 2-PyMe2SiH and 4-PyMe2SiH. It seems that these reactivity differences stem primarily from the governance of two different mechanisms (Chalk-Harrod and modified ChalkHarrod mechanisms). From the observed reactivity order, coordination and electronic effects of dimethyl(pyridyl)silanes have been implicated.
| Original language | English |
|---|---|
| Pages (from-to) | 2645-2652 |
| Number of pages | 8 |
| Journal | Journal of Organic Chemistry |
| Volume | 67 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Apr 19 2002 |
| Externally published | Yes |
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- Organic Chemistry
Cite this
Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane. / Itami, Kenichiro; Mitsudo, Koichi; Nishino, Akira; Yoshida, Jun Ichi.
In: Journal of Organic Chemistry, Vol. 67, No. 8, 19.04.2002, p. 2645-2652.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane
AU - Itami, Kenichiro
AU - Mitsudo, Koichi
AU - Nishino, Akira
AU - Yoshida, Jun Ichi
PY - 2002/4/19
Y1 - 2002/4/19
N2 - Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane is described. The hydrosilylation of alkenes using dimethyl(2-pyridyl)silane (2-PyMe2SiH) proceeded well in the presence of a catalytic amount of RhCl(PPh3)3 with virtually complete regioselectivity. By taking advantage of the phase tag property of the 2-PyMe2Si group, hydrosilylation products were isolated in greater than 95% purity by simple acid-base extraction. Strategic catalyst recovery was also demonstrated. The hydrosilylation of alkynes using 2-PyMe2SiH proceeded with a Pt(CH2= CHSiMe2)2O/P(t-Bu)3 catalyst to give alkenyldimethyl(2-pyridyl)silanes in good yield with high regioselectivity. A reactivity comparison of 2-PyMe2SiH with other related hydrosilanes (3-PyMe2SiH, 4-PyMe2SiH, and PhMe2SiH) was also performed. In the rhodium-catalyzed reaction, the reactivity order of hydrosilane was 2-PyMe2SiH ≫ 3-PyMe2SiH, 4-PyMe2SiH, PhMe2SiH, indicating a huge rate acceleration with 2-PyMe2SiH. In the platinum-catalyzed reaction, the reactivity order of hydrosilane was PhMe2SiH, 3-PyMe2SiH ≫ 4-PyMe2SiH > 2-PyMe2SiH, indicating a rate deceleration with 2-PyMe2SiH and 4-PyMe2SiH. It seems that these reactivity differences stem primarily from the governance of two different mechanisms (Chalk-Harrod and modified ChalkHarrod mechanisms). From the observed reactivity order, coordination and electronic effects of dimethyl(pyridyl)silanes have been implicated.
AB - Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane is described. The hydrosilylation of alkenes using dimethyl(2-pyridyl)silane (2-PyMe2SiH) proceeded well in the presence of a catalytic amount of RhCl(PPh3)3 with virtually complete regioselectivity. By taking advantage of the phase tag property of the 2-PyMe2Si group, hydrosilylation products were isolated in greater than 95% purity by simple acid-base extraction. Strategic catalyst recovery was also demonstrated. The hydrosilylation of alkynes using 2-PyMe2SiH proceeded with a Pt(CH2= CHSiMe2)2O/P(t-Bu)3 catalyst to give alkenyldimethyl(2-pyridyl)silanes in good yield with high regioselectivity. A reactivity comparison of 2-PyMe2SiH with other related hydrosilanes (3-PyMe2SiH, 4-PyMe2SiH, and PhMe2SiH) was also performed. In the rhodium-catalyzed reaction, the reactivity order of hydrosilane was 2-PyMe2SiH ≫ 3-PyMe2SiH, 4-PyMe2SiH, PhMe2SiH, indicating a huge rate acceleration with 2-PyMe2SiH. In the platinum-catalyzed reaction, the reactivity order of hydrosilane was PhMe2SiH, 3-PyMe2SiH ≫ 4-PyMe2SiH > 2-PyMe2SiH, indicating a rate deceleration with 2-PyMe2SiH and 4-PyMe2SiH. It seems that these reactivity differences stem primarily from the governance of two different mechanisms (Chalk-Harrod and modified ChalkHarrod mechanisms). From the observed reactivity order, coordination and electronic effects of dimethyl(pyridyl)silanes have been implicated.
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U2 - 10.1021/jo0163389
DO - 10.1021/jo0163389
M3 - Article
VL - 67
SP - 2645
EP - 2652
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 8
ER -