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

过渡金属催化的对映体配体的不对称反应因其在合成多种生物活性化合物中的广泛应用而引起合成化学家的极大兴趣。尽管作为磷和砷配体的手性诱导剂在不对称合成中具有显著的用途，但由于这类化合物的获得途径有限，与光学活性有机锑配体的不对称反应到目前为止还没有报道。1.光学活性C_2-手性有机锑化合物的合成及其在不对称反应中的应用从(±)-2，2‘-二溴-1，1’-联萘合成了更多的萘基(MASB：3)，通过分离与光学活性钯试剂di-μ-chlorobis{(S)-2-[1-(dimethylamino)ethyl]phenyl-C^1，N}DiPd(II)反应产生的Pd-络合物的非对映异构体混合物，成功地以对映体的形式拆分了它们。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(反应1)、乙酸烯丙基烷基化反应(反应2)和苯乙烯的硅氢化反应(反应3)，发现BINASb(1)是反应2的有用配体，BINAPSb(2)具有很高的不对称反应潜力。在后一反应中，BINAPSb(2)在反应的早期以双齿配体的形式存在，最后以单齿配体的形式存在。2.含苯甲胺和恶唑啉的光学活性C-手性和Sb-手性有机锑化合物的合成及其在不对称反应中的应用以常见的(S)-((S)-(α-methyl-2-di-p-tolylstibanobenzyl)dimethylamine-甲基苄基)二甲胺为原料，合成了C-手性Sb(R/S)-(aryl)[2-(S)-(1-dimethylaminoethyl)phenyl](p-Tolyl)stibane(AMSb：4)及其铬配合物(AMSb-Cr：5)和C-和Sb-手性α(6)。类似的合成路线也可用于以(S)-4-异丙基-2-苯基-2-恶唑啉为原料合成C(S)，(7)。使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)对这些不对称反应有一定的手性辅助作用。较少

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