Catalytic Polymer-Supported Potassium Thiophenolate in Methanol as a Method for the Removal of Ester, Amide, and Thioacetate Protecting Groups

Abstract

Polymer-supported potassium thiophenolate to remove ester, activated amide, and thioacetate protecting groups catalytically in the presence of methanol is reported.

Key words

polymer-supported - thiophenolate - deprotection

References

• 1 Greene TW. Wuts PGM. Protective Groups in Organic Synthesis   2nd ed.:  Wiley and Sons; New York: 1991. 
• 3 Ley SV. Baxendale IR. Bream RN. Jackson PS. Leach AG. Longbottom DA. Nesi M. Scott JS. Storer RI. Taylor SJ. J. Chem. Soc., Perkin Trans. 1  2000,  23:  3815 
• For some recent applications see:
• 4a Jamieson C. Congreave MS. Embiata-Smith DF. Ley SV. Synlett  2000,  1603 
• 4b Jamieson C. Congreave MS. Embiata-Smith DF. Ley SV. Scicinski JJ. Org. Process Res. Dev.  2002,  6:  823 
• 8 Wallace OB. Springer DM. Tetrahedron Lett.  1998,  39:  2693 

2

Argonaut Technologies Catalog 2000, p. 53.

5

General Procedure: Protected compound (1.0 equiv) was dissolved in MeOH/THF (1:1) in a sealed vial and stirred with thiophenolate resin 1 (1.45 mmol/g, 0.2 equiv). The reaction was heated as described herein. When reaction was complete, the resin was removed by filtration and washed with THF. The combined washings were dried in vacuo. If starting material remained, the product was isolated by standard column chromatography.

6

Thiophenolate Resin: Polymer-supported thiophenol was shaken at r.t. under argon with potassium trimethylsilanolate in THF. After 2 d, the resin was rinsed with THF and dried in vacuo (1.45 mmol/g).

7

All compounds gave satisfactory spectroscopic data identical to those reported in the literature.

9

Resin was filtered, washed with CH₂Cl₂ three times, and dried in vacuo before reusing.