Improved Synthesis of Double‐Bridged Tetraselenafulvalenophanes and Formation of Their Conductive Radical Cation Salts

Abstract

The double-bridged tetraselenafulvalenophanes (TSFphanes, 4) were efficiently synthesized by a new method using the deprotection/realkylation sequence of the TSF bisthiolate building block 7. Electrocrystallization of 4b with the Au(CN) 2 − counter-anion gave a radical cation salt that showed

A General Method for the Synthesis of Alkylenedithio- and Bis(alkylenedithio)tetraselenafulvalenes

“…We first examined the lithiation of TSF with 2 equiv of LDA followed by a reaction with methyl 3-thiocyanatopropionate (Scheme ). 1 H and 13 C NMR spectra of the isolated product were apparently different from those of the known 2,6(7)-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ‘),15d suggesting the selective formation of 2,3-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ) in this reaction. 6a, An unambiguous structural determination was done by an X-ray crystallographic analysis of 11 as shown in Figure .

1 Molecular structure of 11 .

…”

“…Construction of the alkylenedithio moiety was achieved by a two-step reaction. First, the methyl propionate protecting group was cleaved by cesium hydroxide, the resulting TSF thiolate being effectively realkylated with bromochloroalkane . Regardless of the number of methylene moieties, compounds 8a − c were obtained in moderate to good isolated yields.…”

“…Instead of the above one-step approach, a stepwise route via a selective monodeprotection of 11 was examined: treatment of 11 with 1 equiv of cesium hydroxide followed by quenching with excess iodomethane gave 6 quantitatively, 15a-c which was readily converted to the alkylendithio-TSFs ( 1a − c ) following the reaction sequence depicted in Scheme .

5 Synthesis of Alkylenedithio-TSFs ( 1a − c ) from 11

…”

A General Method for the Synthesis of Alkylenedithio- and Bis(alkylenedithio)tetraselenafulvalenes

“…We first examined the lithiation of TSF with 2 equiv of LDA followed by a reaction with methyl 3-thiocyanatopropionate (Scheme ). 1 H and 13 C NMR spectra of the isolated product were apparently different from those of the known 2,6(7)-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ‘),15d suggesting the selective formation of 2,3-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ) in this reaction. 6a, An unambiguous structural determination was done by an X-ray crystallographic analysis of 11 as shown in Figure .

1 Molecular structure of 11 .

…”

“…Construction of the alkylenedithio moiety was achieved by a two-step reaction. First, the methyl propionate protecting group was cleaved by cesium hydroxide, the resulting TSF thiolate being effectively realkylated with bromochloroalkane . Regardless of the number of methylene moieties, compounds 8a − c were obtained in moderate to good isolated yields.…”

“…Instead of the above one-step approach, a stepwise route via a selective monodeprotection of 11 was examined: treatment of 11 with 1 equiv of cesium hydroxide followed by quenching with excess iodomethane gave 6 quantitatively, 15a-c which was readily converted to the alkylendithio-TSFs ( 1a − c ) following the reaction sequence depicted in Scheme .

5 Synthesis of Alkylenedithio-TSFs ( 1a − c ) from 11

…”

Self‐Assembly of Folic Acid: A Chiral‐Aligning Medium for Enantiodiscrimination of Organic Molecules in an Aqueous Environment

“…This route involves a combination of very effective synthetic techniques recently developed by our group, namely, one‐pot formation of 1,3‐diselenole‐2‐selone from a terminal alkyne,8 a trialkyl phosphite‐mediated coupling reaction to the TSF derivative, and finally heterocycle formation by transalkylation on a chalcogen atom 9. In addition, we have taken advantage of a deprotection/realkylation protocol of a novel, protected TSF–thiolate building block 5 10. For the first step, methylthioacetylene ( 2 )11 was successively treated with n BuLi, selenium powder, and carbon diselenide, to generate in situ the vinyl anion intermediate ( 3 ), which was then quenched with 3‐thiocyanatopropionic acid methyl ester12 to give a 1,3‐diselenole‐2‐selone derivative ( 4 ) in 73 % yield.…”

Recent Advances in Design and Synthesis of Diselenafulvenes, Tetraselenafulvalenes, and Their Tellurium Analogs and Application for Materials Sciences

“…Two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized from trimethylsilylacetylene by the synthetic approach presented in Scheme 48 [ 99 ]. Using sequential deprotection and realkylation of the bis-thiolate tetraselenafulvalene building block 162 (51% yield), two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized in 25% and 20% yields, respectively ( Scheme 48 ) [ 99 ]. The radical cationic salt 163b with the Au(CN) 2 − anion exhibited very high conductivity at room temperature.…”

A General Method for the Synthesis of Alkylenedithio- and Bis(alkylenedithio)tetraselenafulvalenes

“…We first examined the lithiation of TSF with 2 equiv of LDA followed by a reaction with methyl 3-thiocyanatopropionate (Scheme ). 1 H and 13 C NMR spectra of the isolated product were apparently different from those of the known 2,6(7)-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ‘),15d suggesting the selective formation of 2,3-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ) in this reaction. 6a, An unambiguous structural determination was done by an X-ray crystallographic analysis of 11 as shown in Figure .

1 Molecular structure of 11 .

…”

“…Construction of the alkylenedithio moiety was achieved by a two-step reaction. First, the methyl propionate protecting group was cleaved by cesium hydroxide, the resulting TSF thiolate being effectively realkylated with bromochloroalkane . Regardless of the number of methylene moieties, compounds 8a − c were obtained in moderate to good isolated yields.…”

“…Instead of the above one-step approach, a stepwise route via a selective monodeprotection of 11 was examined: treatment of 11 with 1 equiv of cesium hydroxide followed by quenching with excess iodomethane gave 6 quantitatively, 15a-c which was readily converted to the alkylendithio-TSFs ( 1a − c ) following the reaction sequence depicted in Scheme .

5 Synthesis of Alkylenedithio-TSFs ( 1a − c ) from 11

…”

Self‐Assembly of Folic Acid: A Chiral‐Aligning Medium for Enantiodiscrimination of Organic Molecules in an Aqueous Environment

“…This route involves a combination of very effective synthetic techniques recently developed by our group, namely, one‐pot formation of 1,3‐diselenole‐2‐selone from a terminal alkyne,8 a trialkyl phosphite‐mediated coupling reaction to the TSF derivative, and finally heterocycle formation by transalkylation on a chalcogen atom 9. In addition, we have taken advantage of a deprotection/realkylation protocol of a novel, protected TSF–thiolate building block 5 10. For the first step, methylthioacetylene ( 2 )11 was successively treated with n BuLi, selenium powder, and carbon diselenide, to generate in situ the vinyl anion intermediate ( 3 ), which was then quenched with 3‐thiocyanatopropionic acid methyl ester12 to give a 1,3‐diselenole‐2‐selone derivative ( 4 ) in 73 % yield.…”

Recent Advances in Design and Synthesis of Diselenafulvenes, Tetraselenafulvalenes, and Their Tellurium Analogs and Application for Materials Sciences

“…Two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized from trimethylsilylacetylene by the synthetic approach presented in Scheme 48 [ 99 ]. Using sequential deprotection and realkylation of the bis-thiolate tetraselenafulvalene building block 162 (51% yield), two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized in 25% and 20% yields, respectively ( Scheme 48 ) [ 99 ]. The radical cationic salt 163b with the Au(CN) 2 − anion exhibited very high conductivity at room temperature.…”

A General Method for the Synthesis of Alkylenedithio- and Bis(alkylenedithio)tetraselenafulvalenes

“…We first examined the lithiation of TSF with 2 equiv of LDA followed by a reaction with methyl 3-thiocyanatopropionate (Scheme ). 1 H and 13 C NMR spectra of the isolated product were apparently different from those of the known 2,6(7)-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ‘),15d suggesting the selective formation of 2,3-bis(2-methoxycarbonylethylthio)tetraselenafulvalene ( 11 ) in this reaction. 6a, An unambiguous structural determination was done by an X-ray crystallographic analysis of 11 as shown in Figure .

1 Molecular structure of 11 .

…”

“…Construction of the alkylenedithio moiety was achieved by a two-step reaction. First, the methyl propionate protecting group was cleaved by cesium hydroxide, the resulting TSF thiolate being effectively realkylated with bromochloroalkane . Regardless of the number of methylene moieties, compounds 8a − c were obtained in moderate to good isolated yields.…”

“…Instead of the above one-step approach, a stepwise route via a selective monodeprotection of 11 was examined: treatment of 11 with 1 equiv of cesium hydroxide followed by quenching with excess iodomethane gave 6 quantitatively, 15a-c which was readily converted to the alkylendithio-TSFs ( 1a − c ) following the reaction sequence depicted in Scheme .

5 Synthesis of Alkylenedithio-TSFs ( 1a − c ) from 11

…”

Self‐Assembly of Folic Acid: A Chiral‐Aligning Medium for Enantiodiscrimination of Organic Molecules in an Aqueous Environment

“…This route involves a combination of very effective synthetic techniques recently developed by our group, namely, one‐pot formation of 1,3‐diselenole‐2‐selone from a terminal alkyne,8 a trialkyl phosphite‐mediated coupling reaction to the TSF derivative, and finally heterocycle formation by transalkylation on a chalcogen atom 9. In addition, we have taken advantage of a deprotection/realkylation protocol of a novel, protected TSF–thiolate building block 5 10. For the first step, methylthioacetylene ( 2 )11 was successively treated with n BuLi, selenium powder, and carbon diselenide, to generate in situ the vinyl anion intermediate ( 3 ), which was then quenched with 3‐thiocyanatopropionic acid methyl ester12 to give a 1,3‐diselenole‐2‐selone derivative ( 4 ) in 73 % yield.…”

Recent Advances in Design and Synthesis of Diselenafulvenes, Tetraselenafulvalenes, and Their Tellurium Analogs and Application for Materials Sciences

“…Two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized from trimethylsilylacetylene by the synthetic approach presented in Scheme 48 [ 99 ]. Using sequential deprotection and realkylation of the bis-thiolate tetraselenafulvalene building block 162 (51% yield), two-bridged tetraselenafulvalenophanes 163a , b were efficiently synthesized in 25% and 20% yields, respectively ( Scheme 48 ) [ 99 ]. The radical cationic salt 163b with the Au(CN) 2 − anion exhibited very high conductivity at room temperature.…”