Pd-catalysed cross coupling of terminal alkynes to diynes in the absence of a stoichiometric additive

Abstract

An efficient, room temperature procedure for the cross-coupling of a range of terminal alkynes, using standard Sonogashira cross-coupling conditions (Pd/Cu) is presented. At higher reaction temperatures, head-to-tail or head-to-head dimerisation affords 1,3- and 1,4-disubstituted enynes, respectively as minor products.

Conjugated Microporous Polymers

“…This, in turn, may arise from the more diverse chemistry that occurs for these PPBsfor example, in the formation of 1,3-disubstituted enyene crosslinks [4] -although it is possible that these side reactions might be avoided using alternative reaction conditions. [42] All of the aforementioned CMPs are composed predominantly of carbon and hydrogen. Recently, microporous polysilanes were reported (SA BET up to 1046 m 2 g À1 ).…”

Synthesis of 2,4,6‐trisubstituted naphthalenes via novel copper‐promoted tandem coupling and intramolecular cyclization

“…Unless otherwise noted, the reagents were purchased from Shanghai Chemical Reagent Company and used without further purification. 1 H NMR (400 MHz) and 13 C NMR (100 MHz) spectra were recorded on a Bruker Avance spectrometer using CDCl 3 as the solvent and TMS as the internal standard; chemical shifts were quoted in ppm and J values were given in Hz. Mass spectra (EI, 70 eV) were recorded on a HP5989B mass spectrometer.…”

Palladium‐Catalysed Cross‐Coupling and Related Processes: Some Interesting Observations That Have Been Exploited in Synthetic Chemistry

“…[134,135] Recently the use of Pd/C has proven a surprisingly good catalyst in the Sonogashira coupling reaction of bromo-2-pyrones. [130] In fact this catalytic system is more efficient in a number of cases than more commonly used catalyst/ precatalyst systems, e.g. Pd(OAc) 2 /PPh 3 .…”

“…It was felt that, providing the 2-pyrone was not necessary for this process, the reaction conditions could prove a convenient method for the preparation of 1,3-diynes (Scheme 33). By this method several Pd-containing catalysts were compared and a diverse series of alkynes were homocoupled, [130] which were formed at room temperature. The method is tolerant to a number of functional groups and the substrate scope is good.…”