Alkynylation of steroids via Pd-free Sonogashira coupling

Org Biomol Chem. 2015 May 21;13(19):5542-55. doi: 10.1039/c5ob00559k.

Abstract

Cu-catalyzed Pd-free Sonogashira coupling has been proposed as a straightforward and convenient route to valuable steroidal enynes. A biligand catalyst system based on Ph3P and TMEDA has been designed. The protocol was utilized for the efficient coupling of iodosteroids with diverse terminal alkynes and 1-trimethylsilylalkynes. A possible role of an auxiliary ligand as a phase-transfer catalyst for a sparingly soluble inorganic base (K2CO3) was revealed.