Evans P Andrew, Lai Kwong Wah, Sawyer James R
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
J Am Chem Soc. 2005 Sep 14;127(36):12466-7. doi: 10.1021/ja053123y.
Transition metal-catalyzed [m+n+o] carbocyclization reactions provide powerful methods for the construction of complex polycyclic systems that are generally not accessible through classical pericyclic reactions. We have developed the first regio- and enantioselective crossed intermolecular rhodium-catalyzed [2+2+2] carbocyclization of carbon- and heteroatom-tethered 1,6-enynes with unsymmetrical 1,2-disubstituted alkynes. This study clearly delineates the ligand requirements for obtaining excellent regio- and enantioselectivity. Furthermore, the ability to utilize various electron-withdrawing groups, and to introduce quaternary carbon stereogenic centers, provides the level of versatility necessary for its application to target-directed synthesis. Additional studies on the development and application of this novel methodology to the total synthesis of natural products are currently underway.
过渡金属催化的[m + n + o]碳环化反应为构建复杂的多环体系提供了强有力的方法，而这些体系通常无法通过经典的周环反应得到。我们已经开发出了首例区域和对映选择性交叉分子间铑催化的碳-杂原子连接的1,6-烯炔与不对称1,2-二取代炔烃的[2 + 2 + 2]碳环化反应。这项研究清楚地描绘了获得优异区域和对映选择性所需的配体要求。此外，利用各种吸电子基团以及引入季碳立体中心的能力，为其应用于目标导向合成提供了必要的通用性水平。目前正在对这种新方法在天然产物全合成中的开发和应用进行进一步研究。
