Methyl magnesium amide

Several enamines also participate in these cycloaddition reactions. For example, the addition of methyl lithium to benzaldehyde 5 and the sequential introduction of the vinylogous amide and magnesium bromide results in the cycloaddition elimination product chromene 63 (method G, Fig. 4.33).27 The introduction of methyl magnesium bromide to a solution of the benzaldehyde 5 and two equivalents of the morpholine enamine produces the cycloadduct 64 in 70% yield with better than 50 1 diastereoselectivity (method F). Less reactive enamides, such as that used by Ohwada in Fig. 4.4, however, fail to participate in these conditions. 

Amidation-the Bodroux reaction Finally, amidahon of methyl ester 33 was required to complete the process. To accomplish this transformation, we turned to a reaction first reported in 1904 by Bodroux [12]. The reaction involves activation of an amine by conversion to the magnesium amide using a Grignard reagent. Subsequent reaction of the magnesium amide with the ester produces the carboxamide. 

The final example of bond rearrangement in solution is the magnesium amide 66. Examination of Fig. 9 shows that the nitrogen atoms N1 and N3 are coordinated to the magnesium, whereas the atoms N2 and N4 do not interact with the metal (the molecule has the approximate C2 point symmetry). The rBu groups at N1 and N3 should thus be different from those at N2 and N4, and therefore two resonances should be observed for rBu in the H-NMR spectrum. This, however, is definitely not the case, and the spectrum of 66 shows only one signal in the rm-butyl region down to — 88°C (the methyl... 

When multiple labelling in any of the primed or unprimed positions 8, 9, 12, 13, 19 and 20 is required, the route is slightly modified (Scheme 5). First the ketone is coupled with the anion of triethyl phosphonoacetate (11), as described above (Scheme 3). The ester product 12 is converted into the A -methoxy-A -methylamide (16) by reacting it with the anion prepared by deprotonation of A, 0-dimethylhydroxylamine with BuLi. The amide 16 can now be reacted with methyl magnesium iodide (17) as described above, thus giving access to carotenoids with multiple labelling in the required positions via the multiply labelled ketone 7 [38]. 

Organometallic reagents and alkali metal amides can react via a cyclic transition state (Section II, B, 5) beginning with electrophilic attack at the most basic ring-nitrogen. As a result, sodamide (in dimethylaniline, 145°, 2 hr) yields the 4-amino derivatives (40% yield S)) methyl- or phenyl-magnesium iodides give the 4-adduct quantitatively.s ... 

Raw Materials Methyl chloride 4-Chlorobenzophenone Magnesium Sodium amide ... 

To a suspension of 3.9 grams of potassium amide is slowly added a solution of 19.2 grams (0.1 mol) Of 5H-dibenzo[a,d] cycloheptene in 600 ml of ether with stirring. The suspension is refluxed with stirring for 3 hours, then cooled to room temperature and a solution of 0.1 mol of 3-(N-formyl-N-methyl)-aminopropyl chloride in 100 ml of ether added. The mixture is then refluxed with stirring for 5 hours and then 100 ml of water added. The ether layer is then washed with dilute hydrochloric acid, then water and then dried over magnesium sulfate and evaporated to dryness yielding 5-[3-(N-formyl-N-methyl)-amino-propyl] -5H-dibenzo[a,d] cycloheptene. 

The magnesium bis(amide) Mg(TMP)2 (TMP = 2,2,6,6-tetramethylpiperidide) has been shown to be a useful base in the selective deprotonation of arenes to produce aryhnagne-sium amide intermediates . For example, reaction of Mg(TMP)2 with methyl benzoate... 

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