2.2.6.6- Tetramethylpiperidine magnesium

On the other hand, the predominant formation of the diastereomeric aldols 3 b results from the titanium enolate 1 b of (S )-5,5-dimethyl-4-tert-butyldimethylsilyloxy-3-hexanone. For this purpose, the ketone is first deprotonated with A-(bromomagnesio)-2,2,6,6-tetramethylpiperidine and the magnesium enolate, presumably (E) configurated, formed is thereby treated with hexamethylphosphoric triamide and triisopropyloxytitanium chloride. After sonification, the aldehyde is added to give predominantly aldol adducts 3b the diastereomeric ratio of 3b/2b surpasses 95 5 and the chemical yields range from 85 to 88%53b. 

Bis(2,2,6,6-tetramethylpiperidino)magnesium, (TMP)2Mg. This stable magnesium diamide is obtained by reaction of 2,2,6,6-tetramethylpiperidine, TMPH, in refluxing THF with dibutylmagnesium. 

A remarkable series of inverse crown compounds featuring organic guest moieties encapsulated within host-like macrocyclic rings composed of sodium/potassium and magnesium ions together with anionic amide groups, such as TMP- (TMPH = 2,2,6,6-tetramethylpiperidine) and Pr NT (Pr NII = diisopropylamine), have been synthesized and characterized. Table 12.8.1 lists some examples of this class of inverse crown molecules. 

Ciba Irgafos 168 tr (2,4-di-tert-butylphenyl)phosphate, Trisftribromoneopentyl) phosphate Ciba Flamstab NOR TM 116, a reaction product of N, JV -ethane- 1,2-diylbis (1,3-propanediamine). cyclohexane, peroxidized 4- butylamino-2,2,6, 6-tetramethylpiperidine and 2,4,6-trichloro-l,3,5-triazine Magnesium hydroxide, melamine, and novolac APP/petol-based intumescent systems catalyzed by divalent and transition metal compounds... 

C-3 Substitution. Recently, a new method to promote the regioselective C-3 functionalization of 1,2-benzodiazine was developed using TMP-magnesium-based metalation (TMP = tetramethylpiperidine) that also employs a stoichiometric quantity of BF3-OEt2 (eq 1). Subsequent Pd-catalyzed crosscoupling occurs in moderate yields with bromo- or iodoarenes. 

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