Simple synthetic entries into the tricyclo[5.3.1.13,9]dodecane and 8-oxatetracyclo[5.4.1.13,10.05,9]tridecane ring systems

Abstract

The bis(enolate) of diester 1 undergoes a double intramolecular alkylation reaction with 3-chloro-2-chloromethylprop-1-ene 2 to form the tricyclic product 3 in 75% yield. This conversion represents the first high-yielding route to derivatives of tricyclo[5.3.1.1^3,9]dodecane, an alicyclic ring system of considerable theoretical and structural interest. Diol derivatives 5, 7, 10, 16 and 17 are prepared to investigate further the crystal engineering requirements for obtaining new helical tubuland hosts. The X-ray structures of 5, 10 and 7 reveal one-, two- and three-dimensional hydrogen bonded lattice structures, respectively, despite their remarkable molecular similarity. Solid 5 comprises chains assembled through intermolecular · · · H–O · · · H–O · · · H–O · · · and novel intramolecular alkene · · · H–O hydrogen bonds; while diol 10 forms double layers of diols constructed from recurved spiral chains (four molecules per repeat unit) of intermolecular · · · H–O · · · H–O · · · H–O · · · hydrogen bonds. When crystallised from diethyl ether, the hydroxy groups of 7 are linked · · · H–O · · · H–O · · · H–O · · · around threefold screw axes to give a further example of the helical tubuland lattice. This is a microporous solid with empty tubes of cross-sectional area 17.8 Ų parallel to z. Appropriately functionalised tricyclo[5.3.1.1^3,9]dodecanes undergo efficient intramolecular cyclisation providing compounds 18, 20, 22 and 24 which are the first reported derivatives of 8-oxatetracyclo[5.4.1.1^3,10.0^5,9]tridecane.