Boutland Aaron J, Lamsfus Carlos A, Maitland Brant, Maron Laurent, Stasch Andreas, Jones Cameron
Monash Centre for Catalysis, School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
Université de Toulouse et CNRS, INSA, UPS, UMR 5215, LPCNO, 135 Avenue de Rangueil, F-31077, Toulouse, France.
Chemistry. 2017 Oct 9;23(56):14049-14055. doi: 10.1002/chem.201703061. Epub 2017 Sep 6.
The first examples of magnesium acyls, [(Nacnac)Mg{μ-C(Ph)O}(μ-OR)Mg(Nacnac)] (R=Me, tBu or Ph; Nacnac=[HC(MeCNAr) ] ; Ar=C H Me -2,4,6 ( Nacnac), C H Et -2,6 ( Nacnac), C H iPr -2,6 ( Nacnac)), have been prepared by reductive cleavage of a series of esters using dimeric magnesium(I) reducing agents, [{(Nacnac)Mg} ]. Crystallographic studies reveal the complexes to be dimeric, being bridged by both phenyl-acyl and alkoxide/aryloxide fragments. The crystal structures, combined with results of spectroscopic and computational studies suggest that the nature of the acyl ligands within these complexes should be viewed as lying somewhere between anionic umpolung acyl and oxo-carbene. However, reactions of the acyl complexes with a variety of organic electrophiles did not provide evidence of umpolung acyl reactivity. A number of attempts to prepare alkoxide free magnesium acyls were carried out, and while these were unsuccessful, they did lead to unusual products, the crystallographic and spectroscopic details of which are discussed.
首批镁酰基化合物[(Nacnac)Mg{μ-C(Ph)O}(μ-OR)Mg(Nacnac)]（R = 甲基、叔丁基或苯基；Nacnac = [HC(MeCNAr)₂]；Ar = 2,4,6-三甲基苯基（Nacnac）、2,6-二乙基苯基（Nacnac）、2,6-二异丙基苯基（Nacnac））已通过使用二聚镁(I)还原剂[{(Nacnac)Mg}₂]对一系列酯进行还原裂解制备而成。晶体学研究表明这些配合物为二聚体，由苯基-酰基和醇盐/芳氧基片段桥连。晶体结构结合光谱和计算研究结果表明，这些配合物中酰基配体的性质应被视为介于阴离子型极性反转酰基和氧代卡宾之间。然而，酰基配合物与多种有机亲电试剂的反应并未提供极性反转酰基反应性的证据。人们进行了多次制备无醇盐镁酰基化合物的尝试，虽然这些尝试未成功，但确实得到了不寻常的产物，文中讨论了其晶体学和光谱学细节。
