Novel Spiroannulated 3-Benzofuranones. Synthesis and Inhibition of the Human Peptidyl Prolyl cis/trans Isomerase Pin1

The novel 3H-spiro[1-benzofuran-2-cyclopentan]-3-one skeleton has been madeaccessible by different routes. One- and two-step protocols lead to tricyclic and tetracyclicbenzofuranones 2 and 3, respectively. A four-step synthesis to spirocompound 4 isdescribed. The novel spirocyclic benzofuranones display modest to no inhibition of thehuman peptidyl prolyl cis/trans isomerase Pin1.