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A Practical Method for Selective Cleavage of a tert ‐Butoxycarbamoyl N ‐Protective Group from N , N ‐Diprotected α‐Amino Acid Derivatives Using Montmorillonite K‐10
Author(s) -
Hernández J. Nicolás,
Crisóstomo Fernando R. Pinacho,
Martín Tomás,
Martín Víctor S.
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700296
Subject(s) - chemistry , montmorillonite , cleavage (geology) , toluene , amino acid , protecting group , organic chemistry , stereochemistry , medicinal chemistry , biochemistry , alkyl , geotechnical engineering , fracture (geology) , engineering
A new, practical, and mild procedure for the selective cleavage of a tert ‐butoxycarbonyl group (Boc) in N ‐Boc‐ N ‐acyl‐diprotected amines is described. When applied to α‐amino acids, complete integrity of the stereochemistry was observed. The use of N , N ‐di‐Boc‐α‐amino‐δ‐ and γ‐hydroxy esters provided both δ‐ and γ‐lactones in very good yields. The method is based on the use of Montmorillonite K‐10 either in CH 2 Cl 2 at room temperature or in toluene at 65 °C and is compatible with the presence of a large range of functional and other protecting groups in the substrates. In most cases virtually pure samples are obtained after filtration and removal of solvents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)