Generation of New Active Lanthanide Species and Their Use in Organic Synthesis

1.镱亚胺配合物催化胺的脱氢硅烷化和亚胺的硅氢化反应。本文报道了镱亚胺配合物[Yb（η^2-Ph_2CNAr）（hmpa）_n]催化伯胺和仲胺与三苯基硅烷的脱氢硅烷化反应，得到了高产率的氨基硅烷。在与二苯基和苯基硅烷的反应中，形成二氨基硅烷作为主要产物。虽然正烷基胺和仲烷基胺容易甲硅烷基化，叔烷基胺和芳族胺表现出较低的反应性。此外，还用苯基硅烷和亚胺配合物（At=Ph，C_6H_4F-4）进行了亚胺的硅氢加成反应，得到了单氨基和二氨基硅烷。两种反应在产物选择性和产率方面一致。2.低价钐促进的酰基膦酸酯与两个羰基化合物的三组分偶联：一锅法合成β-羟基膦酸酯。用低价钐实现了酰基膦酸酯和两个羰基化合物的三组分偶联，得到β-羟基膦酸酯。因此，在半催化量的钐金属或SmI_2存在下，酰基膦酸酯与醛反应，以良好的产率得到酰氧基膦酸酯。在SmI_2的促进下，酰氧基膦酸酯与醛或酮的第二次偶联反应生成β-羟基膦酸酯，而不是烯烃。此外，这两个反应可以在一锅中进行。

1. Dehydrogenative Silylation of Amines and Hydrosilylation of Imines Catalyzed by Ytterbium-Imine Complexes. Dehydrogenative silylation of primary and secondary amines with triphenylsilane was catalyzed by ytterbium-imine complexes, [Yb(η^2-Ph_2CNAr)(hmpa)_n], to give aminosilanes in good yields. In the reaction with diphenyland phenylsilanes, diaminosilanes were formed as major products. While n- and sec-alkylamines were readily silylated, tert-alkylamines and aromatic amines exhibited lower reactivities. Moreover, hydrosilylation of imines has been achieved by using phenylsilane and the imine complexes (At=Ph, C_6H_4F-4), giving rise to mono- and diaminosilanes. The two reactions were in agreement as regards the product selectivities and yields.2. Three-Component Coupling of Acylphosphonates and Two Carbonyl Compounds Promoted by Low-Valent Samariums : One-Pot Synthesis of β-Hydroxyphosphonates. Three-component coupling of acylphosphonates and two carbonyl compounds leading to β-hydroxyphosphonates has been achieved with low-valent samariums. Thus, acylphosphonates reacted with aldehydes in the presence of semi-catalytic amounts of samarium metal or SmI_2 to give acyloxyphosphonates -in good yields. The second coupling reaction of the acyloxyphosphonates with aldehydes or ketones promoted by SmI_2 afforded β-hydroxyphosphonates, instead of olefins. Moreover, these two reactions could be carried out in one pot.