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Synlett 2002(12): 1991-1994
DOI: 10.1055/s-2002-35590
LETTER
© Georg Thieme Verlag Stuttgart · New York

‘Safety-Catch’ Propargyl-Based Linker Strategy for the Immobilization of Amines and Carboxylic Acids in SPOS

Maren Fürst, Karola Rück-Braun*
Technische Universität Berlin, Institut für Chemie, Straße des 17. Juni 135, 10623 Berlin, Germany
Fax: +49(30)31479651; e-Mail: krueck@chem.tu-berlin.de;
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Publikationsverlauf

Received 9 August 2002
Publikationsdatum:
20. November 2002 (online)

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Abstract

Integral propargyl alcohol and propargyl chloroformate linkers were developed for a ‘safety-catch’ acid-sensitive linker strategy. The syntheses of the integral propargyl linkers were achieved by direct conversion of the solid support starting from Merrifield resin, hydroxymethylpolystyrene or 4-bromopolystyrene. Amines and carboxylic acids have been coupled and released to demonstrate that transformation of the propargyl units to cobalt carbonyl complexes facilitates the cleavage under mild acidic conditions in high purity.

Key words

alkyne complexes - cobalt - linker - palladium - solid-phase

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18

All resins prepared have been characterized by IR spectro-
scopy and by elemental analysis before and after immobili-zation [resin 1: nitrogen analysis (route A), bromine and nitrogen analysis (route B); resin 2: chlorine and nitrogen analysis] as well as Fmoc-calibration for resin 1.

25

The in situ deprotection protocol of Y. Fukase, K. Fukase, S. Kusumoto, [10] when applied to propargyloxycarbonyl-protected phenylalanine methylester on 1.5 mmol scale, resulted in a product mixture and unsatisfactory product purity.