Halonium‐Initiated Double Oxa‐Cyclization Cascade as a Synthetic Strategy for Halogenated Furo[3,2‐c]pyran‐4‐ones.

A simple method is reported for the preparation of 7-halogenated furo[3,2-c]pyran-4-ones (II) and (III) by a double oxa-cyclization of cyclopropanecarboxylic acids (I).