Conversion of methyl ketones into terminal acetylenes and (E)-trisubstituted olefins of terpenoid origin

Synthesis of Functionalized Benzo[b]thiophenes by the Intramolecular Copper‐Catalyzed Carbomagnesiation of Alkynyl(aryl)thioethers

“…Here, the carbonyl group acts as a directing group [23] and the metalation occurs regioselectively on position 3 of the benzo [b]thiophene ring. Alternatively, the heterocyclic iodide 6 a underwent a Pd-catalyzed [24] Negishi cross-coupling reaction [25] with 4-acetoxybutylzinc bromide [26] 8 (25 8C, 1 h) to provide the polyfunctional benzothiophene 9 in 77 % yield (method B). The third transformation involves an I/Mg-exchange reaction on the iodide 6 d using iPrMgCl·LiCl (À78 8C, 5 min).…”

One-pot synthesis of propynoates and propynenitriles

“…13 C-NMR (100 MHz, CDCl 3 ) (ppm): 154. 2,133.1,130.7,128.7,119.8,86.2,80.8,62.2,14.2;MS (EI) 9,133.6,129.8,114.6,105.8,83.6,62.9,22.0;MS (EI) 139.0,134.0,132.9,130.8,128.9,117.5,105.7,83.5,62.9,21.3;MS (EI) 139.5,134.1,129.2,128.7,127.6,127.3,116.22,105.7,83.2,63.8;MS (EI) 134.4,132.50,128.9,128.9,128.3,128.1,127.9,127.6,114.7,105.7,83.7,63.3;MS (EI) An efficient transformation towards ester or nitril substituted alkynes was herein described. The practical methodology was conducted at low temperature (-78 or -60 o C) in a one-pot manner with assistance of LiHMDS.…”

“…Research work has been widely carried out for the construction of triple bonds from the substrates of different structure. Pioneered by Negishi [9] and Otera, [10] the topic has gained tremendous development thus far. For example, Tajima et al reported a practical preparation of propynoates in the presence of KF.…”

New Norbornyl Derivatives as Woody Fragrant Materials

“…The reaction sequence was performed on endo-2 instead of the endo/exo-mixture to facilitate the analysis of the compounds. Alkyne endo-10 was obtained in 65% yield with diethyl chlorophosphate (ClP(O)(OEt) 2 ) via the corresponding vinyl diethyl phosphate [15]. Condensation of this alkyne endo-10 with MeCHO, followed by LiAlH 4 reduction then provided endo-7a in 33% yield.…”