Electrophilic ‘Umpolung’ Cyclizations of Alkynes in the Synthesis of Polycyclic Aromatic Hydrocarbons

Abstract

Polycyclic aromatic hydrocarbons (PAHs), such as acenes and phenacenes, are important structural motifs which have found great utility in the future of electronics as organic semi-conducting materials. Reliable methods of synthesizing PAHs, particularly the phenacene type, are limited; and modern techniques employ expensive transition metal catalysts. A less explored but potentially superior strategy involves utilizing hypervalent iodine methodology, avoiding the need for transition metal catalysts. In recent studies, a reaction was developed that could couple ortho-biphenylstyrenes intramolecularly in the synthesis of phenanthrenes using only a catalytic amount of iodotoluene, and m-CPBA as an oxidant. In this thesis, we investigate the mechanism of the rearrangement observed in this recently uncovered reaction, and further apply what we have learned toward a novel strategy for electrophilic ‘umpolung’ cyclizations of alkynes in the synthesis of fluorinated PAHs.