Synthesis and characterization of novel chelated dimethylamino lithium alkoxides: molecular structures of [1‐LiOC(C₆H₁₁)₂‐2‐NMe₂C₆H₄]₂ and [1‐LiOCPh₂CH₂‐2‐NMe₂C₆H₄]₂

Abstract

(6) were obtained. The lithium alkoxides 4±6 were characterized by 1 H, 7 Li, and 13 C NMR spectroscopy. Crystal structure determinations of 5 and 6 were carried out. Compounds 5 and 6 are examples of structurally characterized solvent-free chelated dimethylamino lithium alkoxides and 6 is a rare example of this type containing a seven-membered ring.

Synthesis, Structure, and Solution Studies of Lithiated Allylic Phosphines and Phosphine Oxides

“…The discrete centrosymmetric dimer exhibits a central four-atom (LiO) 2 core, reminiscent of a typical lithium alkoxide motif. 36,37 The bridging oxygen atom Notably, there is a high degree of delocalization through the P1−C1 and P1−O1 bonds, showing considerable bond contraction (average of complexes 7−9 are 1.7012 and 1.5182 Å, respectively; see Table 1). This demonstrates that functionalization of the allyl chain with methyl groups at C2 or C3 does not influence the electronics of the α-deprotonated In summary, α-lithiation of the P-allylic systems result in complexes 1−9 exhibiting a degree of delocalization across the allyl chain fragment.…”

“…Lithiation of P3′ with n -BuLi in diethyl ether solution and addition of THF to aid crystallization yielded a crop of orange needle crystals identified as 5 [{Ph 2 P­(O)­CHC­(Me)­CH 2 Li­(THF)} 2 ] (Figure ). The discrete centrosymmetric dimer exhibits a central four-atom (LiO) 2 core, reminiscent of a typical lithium alkoxide motif. , The bridging oxygen atom belonging to the phosphine oxide binds the two monomeric units together [Li1–O1 and Li1′–O1 are 1.884(2) and 1.990(2) Å, respectively], while the Li cation makes an η 2 -electrostatic contact to carbon atoms C2, 2.691(3) Å, and C3, 2.403(3) Å which lie in the region of typical Li–C allyl contacts . The Li atoms coordination sphere is completed by a coordinating THF molecule.…”