1293397-71-3Relevant academic research and scientific papers
Unlocking the 5-exo Pathway with the AuI-Catalyzed Alkoxycyclization of 1,3-Dien-5-ynes
Virumbrales, Cintia,Suárez-Pantiga, Samuel,Marín-Luna, Marta,Silva López, Carlos,Sanz, Roberto
, p. 8443 - 8451 (2020/07/04)
The first general regio- and stereoselective 5-exo gold(I)-catalyzed alkoxycyclization of a specific class of 1,5-enynes such as 1,3-dien-5-ynes has been described, despite 1,5-enynes being known to almost invariably proceed via endo cyclizations under gold-catalysis. The configuration of the terminal alkene in the starting 1,3-dien-5-yne plays a crucial role on the regiochemical outcome of the reaction. A wide variety of interesting alkoxy-functionalized alkylidenecyclopentenes have been synthesized from 1-monosubstituted (E)-1,3-dien-5-ynes. On the contrary, the corresponding Z isomers evolve affording formal 6-endo cyclization products. In addition, mechanistic exploration supports a highly stabilized carbocation as a key intermediate instead of a highly constrained cyclopropyl gold carbene from E isomers, and also accounts for the well differentiated reactivity observed between both E/Z geometrical isomers as well as for the stereochemical outcome of the reaction.
Access to Substituted Thiophenes through Xanthate-Mediated Vinyl C(sp2)-Br Bond Cleavage and Heterocyclization of Bromoenynes
Huang, Guoling,Li, Jian,Li, Jianrong,Li, Jiaming,Sun, Minghua,Zhou, Peng,Chen, Lu,Huang, Yubing,Jiang, Shaohua,Li, Yibiao
, p. 13037 - 13049 (2020/11/26)
An environmentally sustainable strategy for the chemoselective heterocyclization of bromoenynes through a transition-metal-free sulfuration/cyclization process is reported. Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.
A practical, one-pot synthesis of highly substituted thiophenes and benzo[b]thiophenes from bromoenynes and o-alkynylbromobenzenes
Guilarte, Veronica,Fernandez-Rodriguez, Manuel A.,Garcia-Garcia, Patricia,Hernando, Elsa,Sanz, Roberto
supporting information; experimental part, p. 5100 - 5103 (2011/11/29)
An efficient synthesis of thiophenes and benzo[b]thiophenes has been developed from easily available bromoenynes and o-alkynylbromobenzene derivatives. This novel one-pot procedure involves a Pd-catalyzed C-S bond formation using a hydrogen sulfide surrogate followed by a heterocyclization reaction. Moreover, in situ functionalization with selected electrophiles further expands the potential of this methodology to the preparation of the corresponding highly substituted sulfur heterocycles.
