New Method for Stannylation of Cyclopropenes

By: Josephine Nakhla, Chemfiles Volume 10 Article 3

Due to the wide utility of the cyclopropene ring, methods for the synthesis of highly substituted cyclopropenes are of broad interest to the scientific community. Methods to prepare functionalized cyclopropenes currently include preparation of the cyclopropenyllithium species and subsequent treatment with a trialkyltin chloride, which is then followed by a Stille coupling. However, the obvious limitation to this method is that the cyclopropene ring cannot possess base-sensitive functionalities, which can promote side reactions such as ring opening and formation of stabilized anions. Recently, Lam and coworkers developed a method employing Bu3SnCF2CF3 (711063), which in the presence of stoichiometric KF, allowed for the mild stannylation of otherwise sensitive functionalized cyclopropenes (Scheme 2). These building blocks were further elaborated in a Stille reaction to provide highly functionalized tetrasubstituted cyclopropenes (Scheme 3). A protocol was developed by which the stannylation and Stille coupling were conducted in one-pot, further facilitating access to these useful building blocks.


Scheme 2. Stannylation of cyclopropenes using Bu3SnCF2CF3

Scheme 2. Stannylation of cyclopropenes using Bu3SnCF2CF3 (711063)

Scheme 3. Preparation of tetrasubstituted cyclopropenes

Scheme 3. Preparation of tetrasubstituted cyclopropenes

back to top

Materials

     

References

  1. Fordyce, E. A. F.; Luebbers, T.; Lam, H. W. Org. Lett. 2008, 10, 3993.

back to top

Related Links