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The crystalline hexane-soluble metal alkyls [Na(µMe 2 NCH 2 CH 2 NMe 2 ) have been prepared from LiR with an equimolar portion of NaOBu t , KOBu t , RbOC 6 H 2 Bu t 2 -2,6-Me-4, or CsOCH 2 CH(Et)Bu n and for 2-6 the appropriate neutral ligand. X-ray crystal structures of the metal alkyls 2, 3, and 6 are presented; 1 and 4 were described in an earlier communication. Treatment of 5 with Bu t CN afforded the cesium 1-azaallyl Cs{N(R)C(Bu t )C(H)R} ( 7).

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or g Si(TMS) 3 (THF ) 3 ] yielded the appropriate 1 : 1 addition product 2a-2g, which upon hydrolysis gave the corresponding mono-substituted dihydro-1,3,5-triazine HNC(H)NC(H)(R)NCH 3a-3g. 1 H NMR spectral data showed that the 1,4-dihydrotriazine 3f in toluene-d 8 was in equilibrium with its 1,2-dihydro tautomer. Heating 3f with EtOH or H 2 O in an acidic medium led to the facile cleavage of a C-Si bond and the formation of EtOTMS or (TMS) 2 O, respectively. The 13 C and 15 N NMR spectral data are compared with those obtained by B3LYP/6-31+G* computations on the model compound NC(H)NCH 2 NCH. Treatment of 1 with the lithium amidinate [Li{N(TMS)C(Ph)NTMS}] 2 or with 1-azaallyllithium [Li{N(TMS)C(Ph)C(H)TMS}(tmen)], [Li{N(TMS)C(Bu t )C(H)TMS}] 2 or [Li{N(TMS)C(Ph)C(TMS) 2 }(THF ) 2 ] yielded 2-phenyltriazine 5, 4-phenylpyrimidine 6, 4-tert-butylpyrimidine 9 or, in poor yield, the new 4-phenyl-5-trimethylsilylpyrimidine 7, respectively. In the case of 1 and [Li{N(TMS)C(Bu t )C(H)TMS}] 2 an intermediate was isolated-the thermally unstable [Li{N(TMS)C(H)NC(H)NC(H)C(H)C(Bu t )NTMS}] n 8. A pathway is proposed involving the 1,4-addition of the lithium compound to 1,3,5-triazine 1, followed by a 1,3-trimethylsilyl shift, ring-opening and the formation of a new C-C or C-N bond to form the appropriate aromatic heterocycle.