The Synthesis of [2.2]Phanes

Abstract
Methods for the synthesis of a characteristic selection of ortho-, meta-, and para-bridged [2.2]phanes and their heterocyclic analogues are reviewed. 1. Synthesis of [2.2]Phanes by Bridge Formation 1.1. Formation of C-C Bonds 1.1.1. Wurtz Reaction 1.1.2. C-C Coupling through Nucleophilic Acylation with 2-Lithio-1,3-dithiane 1.1.3. C-C Coupling via Phosphonium Ylids 1.1.4. [2.2]Phanes from Elimination Reactions 1.1.5. [2.2]Phanes by Ring Contraction of Other Phanes 1.2. [2.2]Phanes from Rearrangement Reactions 1.3. Formation of C-X Bonds 2. Preparation of [2.2]Phanes from Other Cyclic Compounds with Formation of the Aromatic or Heteroaromatic Rings 2.1. Heterophanes from Paal-Knorr and Related Reactions 2.2. Carbophanes from Diels-Alder Reactions with Benzynes 3. Conclusions