Deprotonative Metalation of Substituted Benzenes and Heteroaromatics Using Amino/Alkyl Mixed Lithium-Zinc Combinations

作者：Snegaroff Katia; Komagawa Shinsuke; Chevallier Floris; Gros Philippe C; Golhen Stephane; Roisnel Thierry; Uchiyama Masanobu^*; Mongin Florence

来源：Chemistry - A European Journal, 2010, 16(27): 8191-8201.

DOI：10.1002/chem.201000543

• cross-coupling
• density functional calculations
• lithium
• metalation
• zinc

Different homoleptic and heteroleptic lithium-zinc combinations were prepared, and structural elements obtained on the basis of NMR spectroscopic experiments and DFT calculations. In light of their ability to metalate anisole. pathways were proposed to justify the synergy observed for some mixtures. The best basic mixtures were obtained either by combining ZnCl(2)center dot TMEDA (TMEDA = N,N,N',N'-tetramethylethylenediamine) with [Li- (tmp)] (tmp = 2,2,6,6-tetramethylpiperidino; 3 equiv) or by replacing one of the tmp in the precedent mixture with an alkyl group. The reactivity of the aromatic lithium zincates supposedly formed was next studied, and proved to be substrate-, base-, and electrophile-dependent. The aromatic lithium zincates were finally involved in palladium-catalyzed cross-coupling reactions with aromatic chlorides and bromides.

• 出版日期2010