Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

Abstract

Buckybowls bearing a C 70 fragment having two alkoxy groups were synthesized and their structural and optical properties were investigated by single crystal X-ray analysis and UV-vis spectroscopy. In the synthesis of dioxole derivative 5b, the regioisomer 5c was also produced. The yield of 5c was increased by increasing the reaction temperature, indicating that the rearrangement might involve the equilibrium between the Pd(IV) intermediates through C-H bond activation.

Synthesis of the C70 Fragment Buckybowl, Homosumanene, and Heterahomosumanenes via Ring-Expansion Reactions from Sumanenone

“…For example, Shao and co-workers reported the synthesis of [7-6-6] fused heteropolycycles from strained trichalcogenasumanene ortho -quinone via one-pot condensation and rearrangement reaction, with naphthalene-1,8-diamine and tellurinate lactones embedded in the heteropolycycles through the tellura -Baeyer–Villiger oxidation of tellurophenes . Our group constructed buckybowls containing a C 70 fragment through a Wagner–Meerwein rearrangement from sumanene ( 1 ) followed by Pd-catalyzed cyclization (Scheme A), showing the utility of a ring-expansion-based synthetic strategy . Several reports about the synthesis and properties of C 70 fragment buckybowls have also been made in recent research .…”

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

“…More strikingly, the Sakurai group has reported the synthesis of a buckybowl fragment of C 70 from a C 60 sumanene fragment through the ring expansion and annulation reactions in three steps including a Wagner–Meerwein rearrangement to transform the five-membered ring to a six-membered ring as a key transformation ( Scheme 68 ) [ 105 – 106 ]. Their synthetic plan to this goal started with the formation of benzylic carbanion using butyllithium followed by the reaction with a range of aromatic aldehydes to generate the arylsumanyl alcohols 312a–e in 96–99% yields.…”

Synthesis and Properties of Diindeno[1,2,3‐cd:1′,2′,3′‐mn]pyrene and Two of Its Aza‐Analogs

“…The incorporation of heteroatoms to these substructures, in order to alter their inherent physical properties, is still elusive which is most likely due to the lack of expedient synthetic methodologies. [10][11][12][13][14][15][16] Indenopyrenes can be prepared by electrophilic aromatic substitution or Pd-catalyzed cross-coupling reaction and CÀ H activation (Figure 1). [17][18][19] For example, Scott and co-workers synthesized several indenopyrenes by Pd-catalyzed CÀ H activation using aryl triflates and their optical properties were thoroughly investigated.…”

“…However, most research is devoted to the synthesis of C 60 fragments. The incorporation of heteroatoms to these substructures, in order to alter their inherent physical properties, is still elusive which is most likely due to the lack of expedient synthetic methodologies [10–16] …”