Anew synthetic strategy (contractive annulation) for the synthesis of highly strained cyclophanes has been conceived and its viability has been demonstrated through an ine-step synthesis of [2](6,1)naphthaleno[1]paracyclophane from [2.2]paracyclophane. Scheme 1. Existing aromatization-based approach to the syntheses of highly strained cyclophanesand selected examples of its use. Scheme 2. Contractive annulation strategy for simultaneously growing the aromatic component of acyclophane and contracting its bridge. DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone,D MSO = dimethylsulfoxide, Ts = 4-toluenesulfonyl.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A new synthetic strategy (contractive annulation) for the synthesis of highly strained cyclophanes has been conceived and its viability has been demonstrated through a nine‐step synthesis of [2](6,1)naphthaleno[1]paracyclophane from [2.2]paracyclophane.

Two-directional contractive annulation of [2.2]paracyclophane has led to the synthesis of anti- [1](1,6)naphthaleno [1](1,6)naphthalenophane (3). This [1.1]cyclophane (SE = 56.6 kcal/mol) consists of two bent and twisted naphthalene units with interplanar distances as short as 2.74 Å. Despite the high strain and structural distortion, 3 was found to be unreactive toward potential cycloaddition partners (TCNE, DMAD) and under UV irradiation.C ontractive annulation (CA) was recently developed as a new strategy for the synthesis of small, strained cyclophanes. 1 It involves the benzannulation of an existing cyclophane using a set of three carbon atoms: a benzylic C(sp 3 ) atom, the bridgehead (ipso) C(sp 2 ) atom to which it is bonded and a neighboring (ortho) C(sp 2 ) atom (Scheme 1).

Work on the synthesis of [2.2]­paracyclophane/9-alkylfluorene hybrids led to the discovery of the rearrangement of cyclopentadienone 7 to cyclophane 6. A DFT computational study revealed that this formal 1,3-alkyl shift occurs in two steps, but requires the participation of a solvent molecule (ethanol). The rearrangement could be avoided by generating 7 under mild conditions and using benzynes as dienophiles to afford the targeted cyclophanes 14 and 16, the latter of which exhibits dual fluorescence emission.