Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Synthesis, Structures, and Solid State Self-Assemblies of Formyl and Acetyl Substituted Triptycenes and Their Derivatives

Starting from triptycene, 2-, (2,6- or 2,7-)­di-, and (2,6,14- or 2,7,14-)­triformyl or acetyl substituted triptycenes were selectively synthesized. The derivatization of the formyl or acetyl substituted triptycenes was then investigated. Consequently, it was found that the formyl-substituted triptycenes could be transformed into cyano substituted triptycene derivatives by the aldoxime formation and dehydration. Acetoxyl- and acetamino-substituted triptycenes were synthesized by Baeyer–Villiger oxidation of acetyl-substituted triptycenes and Beckmann rearrangement of acetyl-oxime triptycenes, respectively. Deacetylation of triacetaminotriptycene provided an alternative way to the synthesis of triaminotriptycene. In addition, 2-ethynyltriptycene could be conveniently synthesized by Corey–Fuchs reaction of 2-formyltriptycene, and 1,3,5-tritriptycenebenzene was obtained in high yield by the dehydration cyclotrimerization of 2-acetyltriptycene. The different functionalized triptycene derivatives and their regioisomers were well characterized by the FT-IR, ¹H NMR, ¹³C NMR, MS spectra, and single crystal X-ray analyses. Moreover, it was also found that 2,6,14-triacetaminotriptycene with the three amide groups paralleled to their connected aromatic rings could self-assemble into a 2D layer with porous structure, and further 3D microporous architecture by the hydrogen-bond network in the solid state

Diastereoselective Synthesis of Cephalotaxus Esters via Asymmetric Mukaiyama Aldol Reaction

We report a protocol for efficient stereoselective installation of the chiral oxygen-containing tetrasubstituted tertiary carbon stereocenter of the side chain of cephalotaxus esters by means of highly diastereoselective Mukaiyama aldol reactions between α-keto esters (<b>2</b>) and a (<i>Z</i>)-α-chloro ketene silyl acetal. This protocol permitted synthesis of cephalotaxus esters including six natural products in good to excellent yields (up to 94%) with high diastereoselectivities (dr up to 97:3) and could be performed on a multigram scale

Competitive Halogen Bond in the Molecular Ferroelectric with Large Piezoelectric Response

Molecular piezoelectrics are attracting tremendous interest because of their easy processing, light weight, low acoustical impedance, and mechanical flexibility. However, reports of molecular piezoelectrics with a piezoelectric coefficient <i>d</i>₃₃ comparable to piezoceramics such as barium titanate (BTO, 90–190 pC/N) have been scarce. Here, we present a uniaxial molecular ferroelectric, trimethylchloromethylammonium tribromocadmium­(II) (TMCM-CdBr₃), in which the halogen bonding might be a possible critical point for the stabilization of one-dimensional (1D) {CdBr₃}⁻ chain and further reservation of its ferroelectricity in such organic–inorganic hybrid crystalline systems. It has a large <i>d</i>₃₃ of 139 pC/N, 1 order of magnitude higher than those of most classically uniaxial ferroelectrics such as LiNbO₃ (6–16 pC/N) and Rochelle salt (∼7 pC/N), and comparable with those of multiaxial ferroelectrics such as BTO and trimethylbromomethylammonium tribromomanganese­(II) (112 pC/N). Moreover, the simple single-crystal growth and easy-to-find polar axis enable it to hold a great potential for applying in the single-crystal form. In light of the strong, specific, and directional halogen-bonding interactions, this work provides possibilities to explore new classes of molecular piezoelectrics and contribute to further developments

Competitive Halogen Bond in the Molecular Ferroelectric with Large Piezoelectric Response

Molecular piezoelectrics are attracting tremendous interest because of their easy processing, light weight, low acoustical impedance, and mechanical flexibility. However, reports of molecular piezoelectrics with a piezoelectric coefficient <i>d</i>₃₃ comparable to piezoceramics such as barium titanate (BTO, 90–190 pC/N) have been scarce. Here, we present a uniaxial molecular ferroelectric, trimethylchloromethylammonium tribromocadmium­(II) (TMCM-CdBr₃), in which the halogen bonding might be a possible critical point for the stabilization of one-dimensional (1D) {CdBr₃}⁻ chain and further reservation of its ferroelectricity in such organic–inorganic hybrid crystalline systems. It has a large <i>d</i>₃₃ of 139 pC/N, 1 order of magnitude higher than those of most classically uniaxial ferroelectrics such as LiNbO₃ (6–16 pC/N) and Rochelle salt (∼7 pC/N), and comparable with those of multiaxial ferroelectrics such as BTO and trimethylbromomethylammonium tribromomanganese­(II) (112 pC/N). Moreover, the simple single-crystal growth and easy-to-find polar axis enable it to hold a great potential for applying in the single-crystal form. In light of the strong, specific, and directional halogen-bonding interactions, this work provides possibilities to explore new classes of molecular piezoelectrics and contribute to further developments

Competitive Halogen Bond in the Molecular Ferroelectric with Large Piezoelectric Response

Molecular piezoelectrics are attracting tremendous interest because of their easy processing, light weight, low acoustical impedance, and mechanical flexibility. However, reports of molecular piezoelectrics with a piezoelectric coefficient <i>d</i>₃₃ comparable to piezoceramics such as barium titanate (BTO, 90–190 pC/N) have been scarce. Here, we present a uniaxial molecular ferroelectric, trimethylchloromethylammonium tribromocadmium­(II) (TMCM-CdBr₃), in which the halogen bonding might be a possible critical point for the stabilization of one-dimensional (1D) {CdBr₃}⁻ chain and further reservation of its ferroelectricity in such organic–inorganic hybrid crystalline systems. It has a large <i>d</i>₃₃ of 139 pC/N, 1 order of magnitude higher than those of most classically uniaxial ferroelectrics such as LiNbO₃ (6–16 pC/N) and Rochelle salt (∼7 pC/N), and comparable with those of multiaxial ferroelectrics such as BTO and trimethylbromomethylammonium tribromomanganese­(II) (112 pC/N). Moreover, the simple single-crystal growth and easy-to-find polar axis enable it to hold a great potential for applying in the single-crystal form. In light of the strong, specific, and directional halogen-bonding interactions, this work provides possibilities to explore new classes of molecular piezoelectrics and contribute to further developments