In Situ Synthesis of Benzyl Chloromethyl Ether and its Use for the Protec- tion and Deprotection of Bifunctional Hydroxyl Compounds (original) (raw)

Article The Effects of Solvent and Added Bases on the Protection of Benzylamines with Carbon Dioxide

2016

The introduction and removal of protecting groups is ubiquitous in multi-step synthetic schemes. From a green chemistry standpoint, however, alternative strategies that employ in situ and reversible protection and deprotection sequences would be attractive. The reversible reactions of CO2 with amines could provide a possible vehicle for realizing this strategy. Herein, we present (1) the products of reaction of benzylamines with CO2 in a variety of solvents with and without the presence of basic additives; (2) new adducts associated with CO2 protected benzylamine in acetonitrile containing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); and (3) the intermolecular competitive acylation of benzylamine and benzyl alcohol and the intramolecular competitive acylation of

Solid-Supported Acids as Mild and Versatile Reagents for the Deprotection of Aromatic Ethers

Organic Letters

p-Toluene sulfonic acid (p-TsOH) immobilized either on polystyrene (PS) or silica (Si) was found to be effective in cleaving aromatic ethers containing isopropyl, tert-butyl, allyl, and benzyl groups, as well as mono-, di-, and trimethoxylated benzyl groups, in moderate to excellent yields (54−95%). These protecting groups could be selectively deprotected when they were simultaneously present on the same or different aromatic rings in a substrate. Protecting groups are important tools in organic synthesis as they have found extensive use in many different areas of complex syntheses of natural products, biomolecules, and materials. 1 Crucial features of protecting groups are their ease of preparation and removal as well as their relative stability toward different reaction conditions. A number of moieties such as benzyl, isopropyl, tert-butyl, and mono-or polymethoxylated benzyl, among others, have been developed as protecting groups for both aliphatic and aromatic hydroxy functionalities. 2 Reaction conditions for preparing and removing these protecting groups have been investigated. 3 New reagents and reaction conditions have been continually developed for protecting and/or deprotecting purposes. 4 Current awareness and interest in green chemistry has prompted many research groups, including ours, to investi

Synthesis of monoprotected derivatives of homo-bifunctional molecules

Reactive and Functional Polymers, 1997

Selective derivatization of one of the two functional groups in a symmetrical homo-bifunctional molecule is always an uphill synthetic task. A novel method for synthesis of mono-protected homo-bifunctional poly(ethylene glycol) (PEG) is described in this work. The methodology utilizes a combination of two protecting groups that are orthogonai to each other for the introduction of one of these groups into symmetrical homo-bifunctional PEG polymers. Different well-known protecting groups, namely the carbobenzyloxy (Z) and the t-butyloxycarbonyl (Boc) groups, have been evaluated for this particular purpose. The approach appears to be straightforward in terms of separation of desired products from other non-desirable products or reactants. The methodology described here might be applicable to any symmetrical homo-bifunctional molecular substance and for synthesis of its corresponding monoprotected derivatives.

1,3-Dipolar cycloadditions of ethoxycarbonyl-nitrile benzylimine, EtOOC C  − CH2C6H5, and synthesis of β-amino acids. Synthesis and reactions of ethyl 2-chloro-2-ethoxyacetate and 2-chloro-2-ethoxyacetyl chloride

Tetrahedron, 1994

The principles of Xkyaoo-hydroxylation of olefm were applied to the preparation of l,Zcyano-amines. The dipole component of this cycloaddition was nihile imines, which formed pynv..olines with olefins. Ring cleavage was accomplished by thennolysis of 3-cacboxypyrazolines, which gave 1,2-cyano-amiues and subsequent hydrolysis gave p-amino acids. The syntheses of the tide reagents were described. Ethyl 2-cNom-2-ethoxy-ace&k. gave selectively oximes, hydrazones. n&ones. and phos&oni~ salts with hydroxylamine, hydrasines. &.ubstituted hydmxylamines and uiphenylphosphine nspedively. The p&sph&ium salt-was used ga Wittig reaction w&h aldehydes to give a-ketoesters. Treatment of the acid chloride with ally1 alcohols and subsequently with a monosubstituted hydroxylamine gave the allylic ester &one. which underwent ikamoleculsx cyclization. Similarly, intramolecular cyclizations were carried out with the allylic ester -nibile oxide and allylic ester -niuile imine systems.