Reductive Coupling of Terpenic Allylic Halides Catalyzed by Cp2TiCl: A Short and Efficient Asymmetric Synthesis of Onocerane Triterpenes
摘要:
Titanocene chloride catalyzes the regioselective alpha,alpha '-homocoupling of terpenic allylic halides. This process has been employed in the short and effective synthesis of terpenoids such as beta-onoceradiene (1), beta-onocerin (2), and squalene (3). Evidence is presented for eta(1)-allyltitanium species being involved in the coupling.
Mild Ti<sup>III</sup>- and Mn/Zr<sup>IV</sup>-Catalytic Reductive Coupling of Allylic Halides: Efficient Synthesis of Symmetric Terpenes
作者:Alejandro F. Barrero、M. Mar Herrador、José F. Quílez del Moral、Pilar Arteaga、Jesús F. Arteaga、Horacio R. Diéguez、Elena M. Sánchez
DOI:10.1021/jo062630a
日期:2007.4.1
Two new efficient methods for the regioselective homocoupling of allylichalidesusing either catalytic TiIII or the combination Mn/ZrIV catalyst have been developed. The regio- and stereoselectivity of the process proved to increase significantly when the Mn/ZrIV catalyst is used as the coupling reagent and when cyclic substituted allylichalides are used as substrates. The use of Lewis acids such
Zur Kenntnis der Triterpene. 191. Mitteilung. Zur Stereochemie des ?-Onocerins
作者:K. Schaffner、R. Viterbo、D. Arigoni、O. Jeger
DOI:10.1002/hlca.19560390121
日期:——
The absolute configuration of α-onocerin (I) at C-5, C-10, C-5′ and C-10′ has been established by degradation of onocerin and of abietic acid (XIV) to an identical acid, (−)-trans-[2,6,6-trimethyl-2-carboxy-cyclohexyl-(1)]-acetic acid (XIII). As the relative configuration of C-5 with regard to C-3 has also been determined, the absolute configuration of C-3 and C-3′ too is known.
The Synthesis of Pentacyclosqualene (8,8'-Cycloönocerene) and the α- and β-Onoceradienes<sup>1</sup>
作者:E. J. Corey、R. R. Sauers
DOI:10.1021/ja01516a054
日期:1959.4
Ageta, Hiroyuki; Shiojima, Kenji; Masuda, Kazuo, Chemical and pharmaceutical bulletin, 1982, vol. 30, # 6, p. 2272 - 2274
作者:Ageta, Hiroyuki、Shiojima, Kenji、Masuda, Kazuo
DOI:——
日期:——
Reductive Coupling of Terpenic Allylic Halides Catalyzed by Cp<sub>2</sub>TiCl: A Short and Efficient Asymmetric Synthesis of Onocerane Triterpenes
作者:Alejandro F. Barrero、M. Mar Herrador、José F. Quílez del Moral、Pilar Arteaga、Jesús F. Arteaga、María Piedra、Elena M. Sánchez
DOI:10.1021/ol050335r
日期:2005.6.1
Titanocene chloride catalyzes the regioselective alpha,alpha '-homocoupling of terpenic allylic halides. This process has been employed in the short and effective synthesis of terpenoids such as beta-onoceradiene (1), beta-onocerin (2), and squalene (3). Evidence is presented for eta(1)-allyltitanium species being involved in the coupling.