a
Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan
b
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8602, Japan
,
Cathleen M. Crudden∗
b
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8602, Japan
c
Queen's University, Department of Chemistry, Chernoff Hall, Kingston, Ontario, K7L 3N6, Canada
› Author AffiliationsThis work was supported by the Japan Society for the Promotion of Science (JSPS KAKENHI 21K05068 and 21H05390 to M.N.) and Amano Institute of Technology. JSPS and Nagoya University are acknowledged for funding of this research through The World Premier International Research Center Initiative (WPI) program.
A desulfonylative homocoupling of benzylic sulfone derivatives through a photoredox Ir catalyst is described. The 3,5-bis(trifluoromethyl)phenyl group is an effective substituent on sulfonyl group in this reaction, providing the structurally diverse multiply arylated ethanes in good yields. The α-deuterated or α-fluorinated sulfones, which can be readily prepared by α-functionalization, were also applicable, highlighting an avenue to synthesize medicinally important structures.
2d
Zhang H,
Zheng X,
Xie N,
He Z,
Liu J,
Leung NL. C,
Niu Y,
Huang X,
Wong KS,
Kwok RT. K,
Sung HH. Y,
Williams ID,
Qin A,
Lam JW. Y. Tang B. Z.
J. Am. Chem. Soc. 2017; 139: 16264
For examples of synthesis of deuterated derivatives, see:
14a
Sawama Y,
Kawajiri T,
Niikawa M,
Goto R,
Yabe Y,
Takahashi T,
Marumoto T,
Itoh M,
Kimura Y,
Monguchi Y,
Kondo S,
Sajiki H.
ChemSusChem 2015; 8: 3773
16Procedure for Desulfonylative Homocoupling of Benzhydryl Sulfone 6a
A 10 mL sealable reaction tube equipped with a magnetic stirring bar and a septum was evacuated, flame-dried under vacuum, cooled to room temperature, and backfilled with Ar. To the glass vessel were added benzhydryl 3,5-bis(trifluoromethyl)phenyl sulfone (6a, 133 mg, 0.3 mmol) and Ir(ppy)3 (2.0 mg, 0.003 mmol). The mixture was evacuated under vacuum and refilled with Ar. This cycle was repeated two additional times. Under an Ar atmosphere, acetone (1.5 mL), degassed H2O (0.15 mL), and i-Pr2NEt (105 μL, 0.6 mmol) were added, and the reaction was sealed and stirred under irradiation (Kessil® PR 160, 456 nm) for 17 h. The solvent was removed under reduced pressure and diluted with EtOAc. The mixture was passed through a pad of silica gel with copious washings with EtOAc (ca. 50 mL). The filtrate was concentrated under reduced pressure. The crude product was purified by PTLC (EtOAc–Hex = 1:100 to 1:50) to afford 1,1,2,2-tetraphenylethane (7a, 48.0 mg, 96%) as a white solid. 1H NMR (400 MHz, CDCl3): δ = 4.77 (s, 2 H), 6.99–7.03(m, 4 H), 7.09–7.17 (m, 16 H). 13C NMR (150 MHz, CDCl3): δ = 56.3, 125.8, 128.1, 128.5, 127.4, 143.4. HRMS (DART) m/z calcd for C26H21 [M – H]+: 333.1643; found: 333.1637.
