253684-22-9Relevant academic research and scientific papers
Pd-Catalyzed Indole Synthesis via C-H Activation and Bisamination Sequence with Diaziridinone
Wang, Jianjun,Sun, Xiaofeng,Hu, Daguo,Shi, Yian
supporting information, p. 7561 - 7565 (2021/10/02)
This work describes an efficient Pd-catalyzed indole synthesis. A wide variety of indoles can be obtained in good yields from readily available vinyl bromides. The reaction likely proceeds through a sequential aryl C-H activation and bisamination of a resulting pallada(II)cycle with diaziridinone.
Synthesis of Highly Substituted Polyenes by Palladium-Catalyzed Cross–Couplings of Sterically Encumbered Alkenyl Bromides and N-Tosylhydrazones
Paraja, Miguel,Barroso, Raquel,Cabal, M. Paz,Valdés, Carlos
supporting information, p. 1058 - 1062 (2017/03/27)
A new method for the synthesis of polysubstituted conjugated dienes is described, through the palladium-catalyzed cross-coupling between N-tosylhydrazones and alkenyl bromides. The reaction proceeds efficiently when a combination of a highly substituted bromoalkene and a hydrazone derived from a ketone are employed, pointing to the convenience of a sterically encumbered environment. This unprecedented process allows for the stereocontrolled preparation of highly substituted dienes and polyenes. (Figure presented.).
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
Morri, Ashok Kumar,Thummala, Yadagiri,Doddi, Venkata Ramana
supporting information, p. 4640 - 4643 (2015/09/28)
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.
The Stille Reaction of 1,1-Dibromo-1-alkenes: Preparation of Trisubstituted Alkenes and Internal Alkynes
Shen, Wang,Wang, Le
, p. 8873 - 8879 (2007/10/03)
The Stille reaction of 1,1-dibromo-1-alkenes 1 with aryl- and vinylstannanes produces different products depending on the reaction conditions. When the reaction is run in toluene or 1,4-dioxane with tris(2-furyl)phosphine (TFP) as the ligand, (Z)-bromoalkenes 2 are obtained stereospecifically in good to excellent yields with most substrates. However, 2-aryl-1,1-dibromo-1-alkenes (1e,1g) having an electron-donating methoxy group in the para- or ortho- position give poor yields. This method has been applied to the one-pot syntheses of stereospecifically trisubstituted alkenes 5. When the Stille reaction is conducted in a highly dipolar solvent (DMF), monobromides 2 and/or internal alkynes 4 are the products. The less reactive phenylstannane favors the formation of alkynes 4, regardless of which ligand is used. More reactive organostannanes (vinyl, furyl) require a very electron rich ligand, tris(4-methoxyphenyl)phosphine, for the formation of alkynes 4. This new method for internal alkyne preparation is general, requires very mild reaction conditions, and gives high yields.
