De Bo Guillaume, Leigh David A, McTernan Charlie T, Wang Shoufeng
School of Chemistry , University of Manchester , Oxford Road , Manchester , M13 9PL , UK . Email:
Chem Sci. 2017 Oct 1;8(10):7077-7081. doi: 10.1039/c7sc02462b. Epub 2017 Aug 23.
A pair of enantioselective switchable bifunctional catalysts are shown to promote a range of conjugate addition reactions in up to 95 : 5 e.r. and 95% conversion. Each catalyst can be switched OFF using conditions that switch the other catalyst ON. Catalyst ON : OFF ratios of up to 98 : 2 and 1 : 99 were achieved, with a ratio of reaction rates of up to 16 : 1 between the ON and OFF states, maintained over complete ON-OFF-ON and OFF-ON-OFF cycles. However, simultaneous operation of the catalyst pair in the same reaction vessel, which in principle could allow product handedness to be switched by simple - isomerisation of the catalyst pair, was unsuccessful. In this first generation complementary pair of enantioselective switchable organocatalysts, the OFF state of one catalyst inhibits the ON state of the other.
一对对映选择性可切换双功能催化剂可促进一系列共轭加成反应，对映体过量比高达95:5，转化率达95%。每种催化剂都可以通过使另一种催化剂开启的条件来关闭。实现了高达98:2和1:99的催化剂开/关比，开态和关态之间的反应速率比高达16:1，在完整的开-关-开和关-开-关循环中保持不变。然而，在同一反应容器中同时使用这对催化剂，原则上可通过催化剂对的简单异构化来切换产物的手性，但未成功。在这第一代互补对映选择性可切换有机催化剂中，一种催化剂的关态会抑制另一种催化剂的开态。
Zotero 插件
