The Dual Role of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in the Synthesis of Terminal Aryl- and Styryl-Acetylenes via Umpolung Reactivity.
The dual role of the bicyclic amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was demonstrated in a synthesis of terminal aryl- and styryl-acetylenes. Mechanistically, a tandem process involving elimination/Umpolung/protonation occurs in a single step to generate terminal aryl- and styryl-acetylenes from geminal dibromoalkenes. The key to the success of this transformation lies in the organobase-mediated generation of the acetylide from the 1-bromoalkynes at room temperature. The unique characteristics of DBU as an inherently safer reagent make it an attractive alternative to previous systems wherein required pyrophoric reagents and nonambient temperatures remain unsolved issues. The procedure does not work for the synthesis of alkyl-acetylenes.
Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology (CSIR-IICT) , Hyderabad, 500007, India.
Ashok Kumar
AK
Morri
Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology (CSIR-IICT) , Hyderabad, 500007, India.
Yadagiri
Y
Thummala
Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology (CSIR-IICT) , Hyderabad, 500007, India.|Academy of Scientific and Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Technology (CSIR-IICT) , Hyderabad, 500007, India.
Venkata Ramana
VR
Doddi