Development of Highly Efficient Catalytic C-C Bond-Forming Reactions Bosed or Conplex Induced Proximity Effect

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The use of dimethyl(2-pyridyl)silyl group (2-PyMe_2Si group) as a removable catalyst-directing group was found to be a powerful strategy for enhancing the efficiency of otherwise sluggish catalytic carbon-carbon bond-forming reactions by taking advantage of attractive substrate-catalyst interaction.For example, the palladium-catalyzed Mizoroki -Heck-type reaction of 2-pyridyldimethyl(vinyl)silanes with organic iodides took place in the presence of Pd_2(dba)_3/P(2-furyl)_3 catalyst to give β-substituted vinylsilanes in excellent yields. The Heck-type coupling occurred even with α- and β-substituted 2-pyridyldimethyl(vinyl)silanes. The one-pot double Mizoroki-Heck-type reaction of 2-pyridyldimethyl(vinyl)silane took place with two different aryl iodides to afford β,β-diarylated vinylsilanes in good yields.A "hard-to-achieve" catalytic intermolecular Pauson-Khand-type reaction was also facilitated by 2-PyMe_2Si group. In the presence of a catalytic amount of Ru_3(CO)_<12>, intermolecular Pauson -Khand-type reaction of alkyne, alkenyldimethyl(2-pytidyl)silane, and carbon monoxide took place to afford various substituted 2-cyclopentenones in good to high yields. The use of removable directing 2-PyMe_2Si group not only realizes a formal catalytic intermolecular Pauson-Khand-type reaction using unstrained alkenes which was previously difficult to achieve, but also realizes acomplete regioselective incorporation of substituents at 4- and 5-positions of 2-cyclopentenone structure.