Synthesis of 15 In a 100 mL round-bottom flask 14 (638 mg, 1.70 mmol) Cs 2 CO 3 (757 mg, 2.32 mmol), and DMF (22 mL) were mixed and stirred at 90 °C for 3 days. Then the mixture was cooled to rt, and DMF was removed under vacuum × 100 mL). The combined organic layers were dried over Na 2 SO 4 , and the organic solvent was removed under vacuum. The crude product was purified by column chromatography on silica gel with a 25:1 mixture of CH 2 Cl 2 :MeOH as eluent to give hemicryptophane precursor 15 as a white solid, Then 300 mL CH 2 Cl 2 and 300 mL H 2 O were added. After thoroughly mixing, the organic layer was separated, and the aqueous phase was extracted with CH 2 Cl 2 MHz): ? 7, p.70 ,
3H); 6.96?6.88 (m, 21H)15 (s, 6H), p.553630 ,
88 (s, 9H), 98?3.60?3, vol.389, issue.3, p.55 ,
On Chiralpak ID column (250 × 4.6 mm), with 1 mL min ?1 as flow-rate, CH 2 Cl 2 /TEA ,
Resolution of Hemicryptophane (±)-16. The pure product of (±)-16 (100 mg) was dissolved in 5.2 mL of CH 2 Cl 2 . On a Chiralpak ID column (250 × 10 mm), with 5 mL min ?1 as flow-rate) as mobile phase, UV detection at 300 nm, 26 injections of 200 ?L were stacked every 7.2 min. Both enantiomers were collected, and the solvent was then evaporated. The first eluted enantiomer, M-16, 46 mg) and the second one, pp.16-52 ,
12 ?L triethylamine was added under argon followed by addition of the solution of Zn(ClO 4 ) 2 (H 2 O) 6 (15 mg, 0.041 mmol, 1 equiv) in 2.5 mL CH 3 OH. After stirring the reaction mixture at room temperature for 4 h, a large amount of precipitate appeared. The precipitate was collected, washed thoroughly with Et 2 O, and dried under vacuum to give the pure complex as a white solid (33 mg, 0.023 mmol, 57% yield) The 1 H NMR spectrum of Zn(II)@16 exhibits complex and broad signals because of the conformational rigidification of the whole structure induced by the metal complexation that gives different isomers, which is similar as the previously reported Zn(II)@ Hemicryptophane complex. 4b For the detailed spectra of 1 H NMR, 041 mmol) in 4 mL CHCl 2 see the Supporting Information. HRMS (ESI-TOF) m, p.16 ,
Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: 10 ,
chiral HPLC reports for resolution of (±)-1 and (±)-16 (PDF) INFORMATION Corresponding Author ,
acknowledges grants from the China Scholarship Council, the Re?gionRe?gion Auvergne-Rho? ne-Alpes, France, for an Accueil Doc Bursary, and ENS-Lyon for an Attractiveness Fellowship for Ph.D studies. A.M. thanks ANR OH-risque for funding, grant number ,
Emergence of Hemicryptophanes: From Synthesis to Applications for Recognition, Molecular Machines, and Supramolecular Catalysis, Chemical Reviews, vol.117, issue.6, pp.4900-490, 2017. ,
DOI : 10.1021/acs.chemrev.6b00847