Selective and multiple functionalization of pyridines and alkaloids via Mg- and Zn-organometallic intermediates.

Quinine, nicotine, and related electron-rich amino-substituted pyridines were readily metalated using LiCl-solubilized TMP (2,2,6,6-tetramethylpiperidyl) bases in the presence of BF(3)·OEt(2). A full pyridine functionalization of all five positions of the pyridine ring can be realized by using an appropriate combination of TMP bases in the presence or absence of BF(3)·OEt(2).

Preparation of 2-magnesiated 1,3,5-triazines via an iodine-magnesium exchange.

Functionalized iodo- and diiodo-1,3,5-triazine derivatives readily undergo an I/Mg exchange with BuMgCl, sBuMgCl, or OctMgBr at low temperatures furnishing 2-magnesiated and 2-zincated 1,3,5-triazines (after transmetalation with ZnCl(2)). This method also offers a convenient access to dimagnesiated triazines. Furthermore, it allows the preparation of functionalized 1,3,5-triazinyl dimers and trimers, interesting for their opto-electronic properties.

Preparation of polyfunctional arylmagnesium, arylzinc, and benzylic zinc reagents by using magnesium in the presence of LiCl.

The presence of LiCl considerably facilitates the insertion of magnesium into various aromatic and heterocyclic bromides. Several functional groups, such as -OBoc, -OTs, -Cl, -F, -CF(3), -OMe, -NMe(2), and -N(2)NR(2), are well tolerated. The presence of a cyano group leads in some cases to competitive reduction of the organic halide to the corresponding ArH compound.