- Rh-Catalyzed Direct Carboxylation of Alkenyl C?H Bonds of Alkenylpyrazoles
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The Rh-catalyzed direct carboxylation of alkenyl C?H bonds was achieved by using pyrazole as a removable directing group. In the presence of 5 mol% RhCl3 ? 3H2O, 6 mol% P(Mes)3, and 2 equiv. of AlMe2(OMe), the alkenyl C?H bond of various alkenylpyrazoles was directly carboxylated in good yields under CO2 atmosphere. Furthermore, several useful transformations of the pyrazole moiety of the product were achieved to afford synthetically useful carboxylic acid derivatives in good yields.
- Saitou, Takanobu,Jin, Yushu,Isobe, Kotaro,Suga, Takuya,Takaya, Jun,Iwasawa, Nobuharu
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supporting information
p. 1941 - 1944
(2020/06/10)
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- Synthesis and crystal structures of two potential gem-di(pyrazolyl)cycloalkane ligands, 1,1-di(pyrazol-1-yl)cyclohexane [C6H10(C3N2H3)2] and 1,1-di(pyrazol-1-yl)cyclopentane [C5H8(C3N2H3)2]
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The species 1,1-di(pyrazol-1-yl)cyclohexane, C12H16N4, crystallizes in the monoclinic space group P21/c with a = 8.340(2), b = 14.281(5), c = 10.153(3) A, β= 106.86(2)°, and Z = 4. The cyclohexane moiety has the chair conformation. The congener, 1,1-di(pyrazol-1-yl) cyclopentane, C11H14N4, while not isomorphous, also crystallizes in space group P21/c with a = 14.350(2), b = 6.776(1), c = 11.043(2) A, β= 100.68(1)°, and Z = 4. The cyclopentane ring has a conformation in which four carbon atoms are essentially coplanar, while the fifth (that with the two pyrazolyl substituents) lies 0.63 A from this plane, resulting in a bend of 41.3° across the C(2)...C(5) vector. The hydrogen atoms in each structure were located directly and their coordinates refined.
- Churchill, Melvyn Rowen,Churchill, David George,Huynh, My Hang Vo,Takeuchi, Kenneth J.,Distefano, Alison J.,Jameson, Donald L.
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p. 659 - 665
(2007/10/03)
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