205877-26-5

1.0 g (2.93 mmol) of Intermediate 6 (1) was dissolved in 10.0 mL of tetrahydrofuran (THF), and 14.64 mL (14.64 mmol) of 1.0 M tetrabutylammonium fluoride solution in THF was added slowly and dropwise at room temperature. The reaction mixture was stirred at room temperature for 5 hours. Upon completion of the reaction, 50 mL of distilled water was added and the organic layers were combined by extracting three times with 50 mL of dichloromethane. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to remove the solvent. The residue was separated and purified by silica gel column chromatography to afford 730 mg (2.78 mmol) of intermediate 6 (2) in 93% yield. The product was identified by LC-MS with molecular formula C20H15N and molecular ion peak (M+) m/z of 270.12.

[1] Tetrahedron Letters, 2010, vol. 51, # 6, p. 917 - 920
[2] Tetrahedron, 2010, vol. 66, # 29, p. 5479 - 5485
[3] RSC Advances, 2013, vol. 3, # 39, p. 17914 - 17917
[4] Organic Letters, 2012, vol. 14, # 15, p. 3970 - 3973
[5] Patent: US2013/292653, 2013, A1. Location in patent: Paragraph 0136-0137