Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306-4390, United States.
J Am Chem Soc. 2015 Jan 28;137(3):1165-80. doi: 10.1021/ja510563d. Epub 2015 Jan 13.
We report the first example of a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by propargyl OR moiety. Radical translocations lead to the boomerang return of the radical center to the site of initial attack where it assists the elimination of the directing functionality via β-scission in the last step of the cascade. The Bu3Sn moiety continues further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions.
我们报道了首例无痕迹导向基团在自由基级联反应中的应用实例。缺电子炔烃中初始进攻的化学和区域选择性由丙炔基 OR 部分控制。自由基迁移导致自由基中心以“回旋镖”的方式回到初始进攻点，在级联反应的最后一步通过β断裂协助导向基团的消除。Bu3Sn 部分通过与亲电试剂以及 Stille 和 Suzuki 交叉偶联反应的进一步反应继续进行。这种选择性自由基转化为可控转化缺电子寡炔烃为可调尺寸的多环带提供了一种新方法。
