Adding a compact dihydromethano (CH2 ) group to a 58π-indene fullerene (C60 (Ind)) creates a 56π-electron dihydromethano/indene fullerene (C60 (CH2 )(Ind)) and raises the LUMO level with only a minimal increase in size. This class of compounds features reduced conjugation that raises the LUMO level, and a high electron mobility because of the small CH2 addend.

[reaction: see text] A metalative 5-endo-dig cyclization reaction of 2-ynylphenoles or anilines effected by BuLi and ZnCl(2) produces 3-zinciobenzoheteroles in excellent yield. These intermediates have been transmetalated to the corresponding cuprates and allowed to react with electrophiles to produce a variety of 2,3-disubstituted benzofurans and indoles.

Closing the ring: Thermally stable but reactive 3‐zinciobenzofurans and indoles were synthesized by metalative cyclization of 2‐ynyl phenols or anilines. Furthermore, a variety of extended π‐conjugated molecules were obtained by Pd‐catalyzed cross‐coupling reactions of these heterocycles with mono‐ or polyhalo‐substituted arenes and alkenes (R2Haln; see scheme; Bn=benzyl).

A divergent method for the synthesis of α,α'-diarylacenaphtho[1,2-c]phosphole P-oxides has been established; α,α'-dibromoacenaphtho[c]phosphole P-oxide, which was prepared through a Ti(II)-mediated cyclization of 1,8-bis(trimethylsilylethynyl)naphthalene, underwent a Stille coupling with three different kinds of aryltributylstannanes to afford the α,α'-diarylacenaphtho[c]phosphole P-oxides in moderate to good yields. X-ray crystallographic analyses and UV/Vis absorption/fluorescence measurements have revealed that the degree of π-conjugation, the packing motif, the electron-accepting ability, and the thermal stability of the acenaphtho[c]phosphole π-systems are finely tunable with the α-aryl substituents. All the P=O and P=S derivatives exhibited high stability in their electrochemically reduced state. To use this class of arene-fused phosphole π-systems as n-type semiconducting materials, we evaluated device performances of the bulk heterojunction organic photovoltaics (OPV) that consist of poly(3-hexylthiophene), an indene-C(70) bisadduct, and a cathode buffer layer. The insertion of the diarylacenaphtho[c]phosphole P-oxides as the buffer layer was found to improve the power conversion efficiency of the polymer-based OPV devices.