Aldehydes Pentaerythritol production

In the pentaerythritol case, the dianion reducing agent is formed from formaldehyde first hydroxide attacks it as a nucleophile, then as a base. The dianion transfers hydride to a different aldehyde, the third aldol product, to... 

These reactions often lead to cyclic acetals that interfere with the formation of high molecular weight products. Useful polyacetals, however, can be formed from pentaerythritol and acetals of di aldehydes ... 

The final example by Severin et al. indicates as to where the dynamic covalent synthesis of superstructures may lead to." Driven by a previous observation that boronic ester-based macrocycles with pendent aldehyde groups could be functionalized with amines, they investigated the possibility of performing boronic ester and imine condensation reactions simultaneously. In the first attempt, a mixture of 3-formylphenylboronic acid 14, pentaerythritol 15, and 1,4-diaminobenzene 16 in tetrahydrofuran/toluene was heated in a flask equipped with a Dean-Stark trap (Figure 8a). Analysis of the formed products revealed the formation of macrocycle 17 as a result of a [4-F2-F2] condensation with a yield of 44%. Prompted by this success, they performed the polycondensation reaction on a mixture of 4-formylphenylboronic acid 18, pentaerythritol 15, and tris(2-aminoethyl)amine 19, rather than the linear 1,4-diaminobenzene (Figure 8b). With a remarkable yield of 82%, the macrobicyclic cage 20 was spontaneously formed as a result of the condensation of six boronic acid molecules, three pentaerythritol molecules, and two triamine molecules. A total of 18 covalent bonds were... 

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