Acid Protecting Groups
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Chapter 3 Protecting Groups - Utah State University
ion.chem.usu.eduChapter 3: Protecting Groups I. Protecting Groups of Hydroxyl Groups Consider the stability and effect of anomeric group! Consider the solubility of starting material (the choice of solvent)! Consider the reactivity of different hydroxyl groups! * DCM is common for pyranoses with 2-3 OH’s. For pyranose with more than 4 OH’s, use DMF or ...
PROTECTING GROUPS 57 Smith: Chapter 7
www.vanderbilt.eduPROTECTING GROUPS 58 Methoxyethoxymethyl ethers (MEM) R-OH → R-OCH2OCH2CH2OMe stable to base and mild acid Formation: - MeOCH2CH2OCH2Cl, NaH, THF - MeOCH2CH2OCH2Cl, CH2Cl2, iPr2EtN TL 1976, 809 Cleavage - Lewis acids such as ZnBr2, TiCl4, Me2BBr2 C 5 H 11 O MEM-O
Protecting Groups Handout A
may.chem.uh.eduProtecting Groups Hydroxyl Protection Methyl Ethers Formation: Stability: Cleavage: Adv./Disadv.:Methyl ethers, with the exception of aryl methyl ethers, are often difficult to remove. However, there are exceptions. AlBr 3,EtSH PhSe-Ph 2P-Me 3SiI Stable to Acid and Base CH 2N 2, SiO 2 or HBF 4 NaH, MeI, THF Methylthiomethyl Ethers (MTM ...
Myers Protective Groups – Silicon-Based Protection of the ...
hwpi.harvard.edu• Silyl groups are typically deprotected with a source of fluoride ion. The Si–F bond stength is about 30 kcal/mol stronger than the Si–O bond. Fluoride sources: Tetrabutylammonium fluoride, Bu4N+F– (TBAF) Pyridine•(HF)x Triethylamine trihydrofluoride, Et N•3HF Hydrofluoric acid Tris(dimethylamino)sulfonium difluorotrimethylsilicate ...
DOD INSTRUCTION 3216
www.esd.whs.milprotecting their confidentiality both during and after the conduction of research. 3. DoD Component review of the ethical, legal, and social implications of emerging, readily available technologies or controversial research, development, testing, and evaluation.