Synthesis of Optically Active Orgnoantimony Compounds and Their Application for Asymmetric Reactions

过渡金属催化的对映体纯配体的不对称反应由于其在合成多种生物活性化合物中的广泛应用而引起了合成化学家的极大兴趣。尽管在不对称合成中作为磷和砷配体的手性诱导剂是非常有用的，但是，由于这类化合物的有限获得，迄今为止还没有报道与光学活性有机锑配体的不对称反应。本论文的主要工作是：1.手性C_2有机锑化合物的合成及其在不对称反应中的应用外消旋C_2-对称的2，2 '-二芳基锑烷-1，1'-联萘（BINASb：1），C_2-不对称的2-二芳基锑烷基-2 '-二苯基膦基-1，1'-联萘（BINAPSb：2），2-二芳基锑烷基-2 '-二甲氨基-1，1'-联萘 ...更多信息 以（±）-2，2 '-二溴-1，1'-联萘为起始原料，合成了2-甲基-1，1 '-联萘（MASb：3），并将其与二-μ-氯代双{（S）-2-[1-（二甲氨基）乙基]苯基-C^1，N}二钯（II）反应生成的钯配合物的非对映体混合物进行拆分，得到了对映体纯的2-甲基-1，1'-联萘。通过对几个不对称反应的研究，如前手性酮的不对称还原（反应1）、乙酸烯丙酯的烯丙基烷基化（反应2）和苯乙烯的硅氢加成（反应3），发现BINASb（1）是反应2的有效配体，BINAPSb（2）对反应3具有很高的潜力。在后一个反应中，BINAPSb（2）在反应的早期应起双齿配体的作用，在反应的最后阶段应起单齿配体的作用。2.具有光学活性的C-手性和Sb-手性含苄胺和恶唑啉结构的有机锑化合物的合成及其在不对称反应中的应用以普通的（S）-（α-甲基苄基）二甲胺为原料，合成了（α-甲基-2-二对甲苯基锑苄基）二甲胺（AMSb：4）及其铬配合物（AMSb-Cr：5）和C-和Sb-手性Sb（R/S）-（芳基）[2-（S）-（1-二甲氨基乙基）苯基]（对甲苯基）锑（6）。以（S）-4-异丙基-2-苯基-2-恶唑啉为起始原料，采用类似的合成路线，合成了C（S），Sb（R/S）-芳基[2-（2-恶唑啉基）苯基]（对甲苯基）锑烷（7）。利用这些配体进行的不对称反应表明，化合物7对反应2是有效的，尽管其他配体（4、6）作为这些不对称反应的手性助剂的能力有限。少

Transition metal-catalyzed asymmetric reactions with enantiopure ligands have been of much interest for synthetic chemists because of their wide applicability in the synthesis of a variety of biologically active compounds. Despite remarkable usefulness as a chiral inducer of phosphorous and arsenic ligands in asymmetric synthesis, however, asymmetric reactions with optically active organoantimony ligands have not been reported so far due to the limited access to this class of compounds. In these points of view, we planed to establish a versatile route for the synthesis of optically active organoantimony compounds and to investigate their potential for chiral inducer in asymmetric reactions.1.Synthesis of Optically Active C_2-Chiral Organoantimony Compounds and Their Use for Asymmetric ReactionsRacemic C_2-Symmetrical 2,2'-diarylstibano-1,1'-binaphthyl (BINASb:1), C_2-unymmetrical 2-diarylstibano-2'-dipheny phosphano-1,1'-binaphthyl (BINAPSb:2), 2-diarylstibano-2'-dimethylamino-1,1'-bin … More aphthyl (MASb:3) has been prepared from (±)-2,2'-dibromo-1,1'-binaphthyl and they could be successfully resolved in enantiopure form via separation of diastereomeric mixture of the Pd-complex arose from the reaction with optically active palladium reagent such as di-μ-chlorobis{(S)-2-[1-(dimethylamino)ethyl]phenyl-C^1,N}dipalladium(II). Research on several asymmetric reactions, such as asymmetric reduction of prochiral ketones (Reaction 1), allylic alkylation of allyl acetate (Reaction 2), and hydrosilylation of styrene (Reaction 3) by use of these organoantimony ligands as chiral auxiliaries revealed that BINASb (1) was a useful ligand for the Reaction 2 and BINAPSb (2) had high potential for the reaction 3. In the latter reaction, BINAPSb (2) should function as bidentate ligand at the early stage of the reaction and as monodentate ligand at the last stage.2.Synthesis of Optically Active C-Chiral and Sb-Chiral Organoantimony Compounds Bearing Benzylamine and Oxazoline Moieties and Their Use for Asymmetric ReactionsThe title compounds, C-chiral (S)-(α-methyl-2-di-p-tolylstibanobenzyl)dimethylamine (AMSb:4) and its chromium complex (AMSb-Cr:5), and C- and Sb-chiral Sb(R/S)-(aryl)[2-(S)-(1-dimethylaminoethyl)phenyl](p-Tolyl)stibane (6) has been synthesized from common (S)-(α-methylbenzyl)dimethylamine. Similar synthetic route could be applied to the synthesis of C(S),Sb(R/S)-aryl[2-(2-oxazolino)phenyl](p-tolyl)stibane (7) from (S)-4-isopropyl-2-phenyl-2-oxazoline. The asymmetric reactions by use of these ligands showed that the compound 7 was effective for the Reaction 2, although the other ligands (4〜6) had modest ability as chiral auxiliary for these asymmetric reactions. Less