Protecting Groups Handout A

CHEM 6352 Organic Reactions & Synthesis

CHEM 6352 Organic Reactions & Synthesis Chiral Pool Adapted and expanded from: Wyatt and Warren, “Organic Synthesis,” Wiley, 2007, Ch. 23: The Chiral Pool

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PROTECTING GROUPS IN ORGANIC SYNTHESIS

Protecting Groups: A Necessary Evil 3 Note, however, that each protecting group incorporated in a multi-step synthesis increases the synthesis by two non-productive steps reducing the overall yield and efficiency of the synthesis.

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Synthesis and Structure of Alcohols - Rutgers University

Nomenclature of Diols (Glycols) Diols are compounds with two hydroxyl groups. They are named as for alcohols except the suffix –diol is used, and two numbers are required to locate the –OH’s. Nomenclature of Phenols A phenol always involves a benzene (type) ring, and often the terms ortho, meta and para (meaning 1,2

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Reactions of Alcohols - Rutgers University

(Two) Unique Reactions of Diols i) Pinacol Rearrangement The pinacol rearrangement is a formal dehydration. Mechanism The protonation of the hydroxyl is followed by ionization. The tertiary carbocation rearranges with a methyl shift to produce a cation with resonance. The rearranged product is deprotonated to generate the final product.

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CHAPTER 7 ALCOHOLS, THIOLS, PHENOLS, ETHERS

Oxidation of Alkenes to Vicinal Diols Compounds with hydroxyl groups on adjacent carbons are called vicinal diols. Oxidation of alkenes with cold KMnO 4 or OsO 4 provides occurs with syn addition and provides cis vicinal diols. Trans vicinal diols can be prepared by ring

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Protecting Groups in Organic Synthesis-1 Ready

diols can be protected as diacetals: OO O O OH HO OH OH OH O CSA, CH(OMe) 3 MeOH OMe OH OMe OH OMe Ley, Perkin 1, 1997, 2023 Esters as protecting groups In general, ease of introduction and removal is function of sterics and electronics usually: R OH + O R' LG R O O R' egs O R'Cl O Cl Cl Cl 'Yamaguchi conditions' more often for ...

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Polyurethane: An Introduction - IntechOpen

weight diols (ethylene glycol, 1,4-butanediol, 1,6-hexanediol), cyclohexane dimethanol, diamines, hydroxyl-amines (diethanolamine and triethanolamine) are used as chain extenders in PU synthesis while those with functionality 3 or > 3 are used as crosslinkers.

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Chapter 7: Alkenes: Reactions and Synthesis

Oxidation of Alkenes to 1,2-Diols and Carbonyl Hydroxylation: formal addition of HO-OH across the p-bond of an alkene to give a 1,2-diol. This is an overall oxidation. 1) OsO4 2) NaHSO3 OH OH H H syn addition H H O Os O O O osmate ester intermediate - not usually isolate - NaHSO3breaks down the osmate ester to the product

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Myers Protective Groups – Silicon-Based Protection of the ...

RO Si i-Pr i-Pr i-Pr RO Si Et Et i-Pr RO Si CH3 CH3 CH3 ROH ROH O Si O O Si i-Pr-Pr i i-Pr R R RO Si CH3 CH3 t-Bu RO Si Et Et Et RO Si CH3 CH3 i-Pr RO Si Ph Ph t-Bu O R O R Si t-Bu t-Bu Myers Protective Groups – Silicon-Based Protection of the Hydroxyl Group Chem 115 General Reference: Greene, T. W.; Wuts, P. G. M. Protective Groups In Organic Synthesis, 3rd ed. …

1. Introduction to polyurethanes - Library of Congress

chemistry of the polyaddition reaction between diisocyanate and diols to form polyurethane. The first commercial applications of polyurethane polymers, for millable elastomers, coatings and adhesives, were developed between 1945 and 1947, followed by flexible foams in 1953 and rigid foams in 1957. Since that

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Reduction Reactions - uni-regensburg.de

Anti-1,3-Diols. A number of methods have been developed for forming the anti-1,3-diol from the corresponding chiral 2-hydroxy-ketone. All rely on the so-called DIRECTED REDUCTION which takes advantage of the intramolecular hydride transfer through a well-defined 6-

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