Incorporation of main group elements into the π-conjugated frameworks is a sophisticated strategy to alter the fundamental nature of the parent conjugated πsystems, giving rise to attractive electronic and photophysical properties that are otherwise inaccessible with classic carbon-or metal-based materials. Out of all πconjugated heterocycles, those that are structurally constrained by tethered aryl substituents surrounding the main group center deserve a great deal of attention because not only do they commonly possess the maximum efficiency of π-conjugation and intermolecular interaction, but they also enjoy remarkable thermal and morphological stabilities that are especially crucial for solid-state performances. In certain cases, elucidation of the behavior of such compounds may additionally provide sufficient perspective toward graphene materials doped with main group elements, which are widely considered as potential next-generation optoelectronic materials. In this review, we will specifically focus on historical developments of structurally constrained polycyclic π-electron systems particularly of those with boron, nitrogen, silicon, or phosphorus atoms annulated directly into the center of π-conjugated systems. CONTENTSReview pubs.acs.org/CR

Structural constraint in B,N-phenylated dibenzoazaborine alters the π-conjugation mode and furnishes intense deep-blue emission and intriguing electrochemical properties.

No abstract

Catalyst‐free 1,2‐carboboration of ynamides is presented. Readily available aryldichloroboranes react with alkyl‐ or aryl‐substituted ynamides in high yields with complete regio‐ and stereoselectivity to valuable β‐boryl‐β‐alkyl/aryl α‐aryl substituted enamides which belong to the class of trisubstituted alkenylboronates. The 1,2‐carboboration reaction is experimentally easy to conduct, shows high functional group tolerance and broad substrate scope. Gram‐scale reactions and diverse synthetic transformations convincingly demonstrate the synthetic potential of this method. The reaction can also be used to access 1‐boraphenalenes, a class of boron‐doped polycyclic aromatic hydrocarbons.