Reagents water-sensitive

Lead tetraacetate and periodic acid complement one another in their applicability as reagents for glycol cleavage. The water sensitive lead tetraacetate is used in organic solvents, while periodic acid can be used for cleavage of water-soluble diols in aqueous medium. 

The oxidation of alcohols is an important reaction in organic chemistry. While this transformation is traditionally performed in organic solvents, the use of aqueous orgarric solutions has just recently become a field of intense study (1-6). The effect of water on transition metal-catalyzed reactions, however, remains widely unexplored as most of these reactions require dry organic solvents to avoid decomposition of the transition metal catalyst, of water sensitive reagents, and/or intermediates by a nucleophilic attack of water (1). Comparative studies focusing on the effect of water as a co-solvent on the catalyst and the proceedings of a reaction are therefore rare (7). 

In boron enolate-mediated aldol reactions, stoichiometric amounts of boron reagents are necessary. However, it has been reported that only a catalytic amount of a boron source is sufficient for boron enolate-mediated aldol reactions in water (Scheme 65).302 It should be noted that even water-sensitive boron enolates can be successfully employed in water. 

As noted, sol-gel syntheses for materials based on water-sensitive reagents, such as titanium isoproproxide, must be carried out under low pH20 conditions, which are typically achieved using either an inert atmosphere box (glove box) or under laboratory conditions using a Schlenk-line.73 The Schlenk-line, shown in Fig. 2.4,71 consists of a dual manifold arrangement with one line... 

Despite the obvious benefits outlined above, water cannot always used as a solvent for Diels-Alder reactions. If both reagents are solid, then the reaction will be very slow, if it occurs at all. Also, some substrates possess water-sensitive groups which precludes the use of water as a solvent. 

Mixed carbonates and alkyl carbamates having long alkyl chains were prepared in aqueous alcoholic medium by reaction with chloroformates and isocyanates, respectively, demonstrating that water-sensitive reagents can be used in aqueous media on account of the significantly higher reactivity of sucrose as compared to water and simple alcohols.130,132 The higher stability towards basic conditions of the carbamates as compared to esters or carbonates is such that these materials can be used in basic pH formulations. 

All of Grignard reagent 31 from Protocol 4A assume toxic, water sensitive... 

The usual precautions taken when working with air- and water-sensitive reagents must be employed for working with organocopper compounds. 

These reagents allow coupling without preactivation and they do not react with primary amine groups. As discussed for BOP, the quantity of base is important and the pH should be maintained at 9-10. They are soluble in the common solvents (CH2Q2, DMF, NMP) used in SPPS and are not water sensitive. They are solids, stable, and usable without preactivation. 

Reactions with Water-Sensitive Reagents such as Grignard Reagents, Lithium Alkyls, or Zinc Oiganyls [375] on Solid Phases... 

Horton and Jewell431 examined various reagents for the oxidation to ketones of carbohydrates with isolated secondary hydroxyl groups and concluded that DMSO-Ac20 is the most satisfactory. For a ketone that is water-sensitive, this oxidant has the particular advantage that all reagents can be removed by simple lyophilization. Dimethyl sulfoxide in combination with acetic anhydride effects oxidative re-... 

Thallium(Ill) trifluoroacetate (TTFA), TI(OCOCF3)3. Mol. wt. 543.43 (at. wt. Tl 204.37). The reagent is a water-sensitive solid which decomposes above 100° without melting. Supplier Aldrich. 

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