Expansion of Thiele’s Acid Chemistry in Pursuit of a Suite of Conformationally Constrained Scaffolds

The Diels–Alder dimer of cyclopentadiene
carboxylate, Thiele’s
acid has conformational properties that make it attractive as a molecular
scaffold for applications in supramolecular and biological chemistry.
However, a lack of known reaction methodology for derivatives of Thiele’s
acid (or the corresponding esters) has hampered its utilization in
these fields. We describe an improved preparation of Thiele’s
esters and survey the chemistry of these versatile intermediates.
As part of this effort, we also describe the synthesis of a suite
of Thiele’s acid (or ester) analogues spanning a broad range
of cleft angles.