Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

• Mingfeng Yu,
• Joseph K.-H. Wong,
• Cyril Tang,
• Peter Turner,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 37–41, doi:10.3762/bjoc.11.6

• ) effects this conversion in near-quantitative yields. Compared to existing methods, these conditions are relatively mild and operationally simple, requiring only reaction at room temperature for six hours (TFA) or overnight (HCl). Keywords: Brønsted acids; click chemistry; deboration; dipyrrins; F-BODIPYs

• diversifying the F-BODIPY framework [9]. F-BODIPYs are readily prepared by condensing aldehydes, acyl chlorides or anhydrides with pyrroles and trapping the resulting dipyrrin in situ with boron trifluoride [9][10][11]. F-BODIPYs are generally stable and chemically robust, with photophysical properties that

• , several recent reports have detailed methods for converting F-BODIPYs 1 to the parent dipyrrins 2 (Scheme 1) [15][16][17][18][19]. Crawford and Thompson first proposed the BF2 unit as a protecting group for dipyrrins in 2010, and applied strong base under forcing conditions to effect the deprotection