Proton methods

Use of compounds with no enolisable protons. Methods of avoiding ambiguity in cross condensations. ... 

The kinetically controlled protonation method may also be applied to the determination of the conformational free energy of C-methyl groups in piperidines. For example, protonation of 1,5-dimethylpiperidine (in which 13C is located in the /V-CH3 group) in dodecane and estimation of the ions produced by 13C-NMR spectroscopy gives AG20° of 1.5 0.1 kcal mol-1 for the 3-methyl group.169... 

Alkynes are also reduced to ds-alkenes by the hydroboration-protonation method. ... 

In contrast, there is little information on systems where the stereogenic center is produced by the incoming proton (method ). 

High-resolution proton methods for polymers, MAS and CRAMPS... 

Following the bound proton method used for a mixture in Example 3 of Chapter 5, we can write for the total acid proton concentration... 

Similar methods are available that are based on solid-state proton nuclear magnetic resonance spectroscopy. Proton methods are less discriminating than the equivalent carbon-13 method, being based on a two-phase model of semicrystalline morphology. In their favor, they are several orders of magnitude faster than the carbon-13 method and the equipment required is much cheaper. 

The thiophosphole-alcohols 5 (Scheme 5.3) have been used for further functionalization. However, the protonation method described in Sect. 5.2.1 could not be applied because of the reactivity of the dienic part of phospholes. An alternative method consists in the replacement of the hydroxyl group by the better leaving group acetoxy (Scheme 5.9), even though the primary nature of the acetoxy derivative 12 required harsh conditions for the subsequent nucleophilic substitution. Nevertheless, phosphole-amines 13 [45] and phosphole-phosphines 14 [46, 73] could be obtained in good to moderate yields. 

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