Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

Abstract

Compound Et3 SiOCH2 NMe2 transfers Me2 NCH2 to R2 NH (R2 =Et2 , PhMe, [Cr(η(6) -C6 H5 )(CO)3 ]Me, PhH) to form previously unknown diaminomethanes, Me2 NCH2 NR2 and, in the case of R2 =PhH, the triamine Me2 NCH2 N(Ph)CH2 NMe2 . The diaminomethanes exhibit an unreported disproportionation to a mixture of (R2 N)2 CH2 , (Me2 N)2 CH2 , and Me2 NCH2 NR2 , which can be trapped as their [Mo(CO)4 (diamine)] complexes. Whereas PhMeNCH2 NMe2 is a labile material, the metal-substituted ([(η(6) -C6 H5 )Cr(CO)3 ]MeNCH2 NMe2 is a stable material. The triamine Me2 NCH2 N(Ph)CH2 NMe2 is unstable with respect to transformation to 1,3,5-triphenyltriazine, but is readily trapped as the bidentate-triamineMo(CO)4 . All metal complexes were characterized by single-crystal X-ray diffraction.

Aminomethyl Transfer (Mannich) Reactions Between an O‐Triethylsilylated Hemiaminal and Anilines, RnC6H5−nNH2 Leading to New Diamines, Triamines, Imines, or 1,3,5‐Triazines Dependent upon Substituent R

“…We have used the system with secondary amines to form a series of unusual diamines and reported as ingle reaction with aniline. [1] The latter reaction resulted in good yields of the hexahydro-1,3,5-triphenyl-1,3,5-triazines, presumably via the transformation shown in Scheme 1.…”

“…Overall the facile transfer of Me 2 NCH 2 group to anilinesh as been demonstrated using triethylsiloxy hemiaminal Et 3 SiOCH 2 NMe 2 (1). Furthermore, the outcomeo ft he reaction is dependent upon the nature of the substituent on the phenylr ing:e lectron-donating groups leading directly to 1,3,5triazines, electron withdrawing groups to diamines and triamines under mild conditions.…”

“…The only other such imine structurer eported, also with ab ulky substituent on nitrogen, CH 2 =NAr (Ar = 2,6-(2,4,6-Me 3 C 6 H 2 ) 2 C 6 H 3 ), also exhibits as imilar NH 2 group orthogonal to the aryl group with as imilar CÀN methylene bond length of 1.247 . [15] In both the reported imine and ours, the methylene protons can be noted by 1 HNMR spectroscopy as ap air of doublets, for 4 at 6.12 ( 1 J HH = 18 Hz) and 7.13 ppm ( 1 J HH = 12 Hz), respectively.I mine 4,u nlike the previously reported example, is av ery thermally and oxida-tively stable materiala nd its possible chemicalr eactivity is currently under investigation.…”

“…We recently reported that Et 3 SiOCH 2 NMe 2 (1)i sahighly efficient Mannich reagent, with the ability to transform ar ange of RE-H species, E = O, S, N, P, to the corresponding dimethylamino derivatives, RE-CH 2 NMe 2 ,u nder mild conditionsa nd generally without the need for either ac atalyst or an activating coreagent. [1,2] In each case, Et 3 SiOH is formed whichi se asily removed under vacuum. In the case of the reaction of 1 with aniline the final product obtainedw as hexahydro-1,3,5-triphenyl-1,3,5-triazine,( PhNCH 2 ) 3 .H owever,u sing NMR spectroscopy we were able to observe the transience of the previously unreported triamine, (Me 2 NCH 2 ) 2 NPh and to trap and characterize its Mo(CO) 4 derivative.…”

Pentaborate(1-) Salts and a Tetraborate(2-) Salt Derived from C2- or C3-Linked Bis(alkylammonium) Dications: Synthesis, Characterization, and Structural (XRD) Studies

“…Likewise, 4 has been previously obtained in very low yield (a few crystals) as a by-product of a reaction of B(OH) 3 with B 2 (NMe 2 ) 4 followed by crystallization from water [21]. N,N,N'N'-Tetraakyldiaminomethane cations are less stable than the tetrasubstituted diaminoethane or diaminopropane cations in aqueous solution and the formation of the corresponding dialkylammonium pentaborate(1-) salts 3 and 4 in high yields is not unexpected and further demonstrates the ready cleavage of the C-N aminal bonds [22][23][24][25]. Further characterization data for 1 and 4 are reported within this manuscript.…”