Evans P Andrew, Robinson John E, Baum Erich W, Fazal Aleem N
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
J Am Chem Soc. 2002 Jul 31;124(30):8782-3. doi: 10.1021/ja026351q.
Transition metal-catalyzed cycloaddition reactions represent powerful methods for the construction of complex polycyclic systems. We have developed a new intermolecular metal-catalyzed [4 + 2 + 2] cycloaddition of heteroatom-tethered enyne derivatives with 1,3-butadiene. This study demonstrates that excellent selectivity can be obtained for the heterocycloaddition adducts through the judicious choice of silver salt. The development of the tandem rhodium-catalyzed allylic substitution [4 + 2 + 2] cycloaddition provides a convenient three-component coupling that circumvents the prior formation of the enyne derivative. Finally, the introduction of a stereogenic center at C-2 leads to a diastereoselective cycloaddition, which provides a powerful new method for the construction of bicyclic octanoid ring systems applicable to target directed synthesis.
过渡金属催化的环加成反应是构建复杂多环体系的有力方法。我们开发了一种新型的分子间金属催化的杂原子连接的烯炔衍生物与1,3 - 丁二烯的[4 + 2 + 2]环加成反应。该研究表明，通过明智地选择银盐，可以获得杂环加成产物的优异选择性。串联铑催化的烯丙基取代[4 + 2 + 2]环加成反应的发展提供了一种便捷的三组分偶联反应，避免了烯炔衍生物的预先形成。最后，在C - 2处引入一个手性中心导致非对映选择性环加成反应，这为构建适用于靶向合成的双环辛烷类环体系提供了一种强大的新方法。
