分两步制备了两个3,3'-二烷基-5,5',6,6'-四甲基-1,1'-联苯-2,2'-二醇(其中烷基= t -Bu,金刚烷基),并将其拆分作为薄荷醇磷酸酯衍生物。将每种双酚盐的双钾盐加到各种Mo(N-芳基)(CHR)(OTf)2(DME)络合物中,生成Mo(N-芳基)(CHR)(双酚盐)类型的外消旋和对映纯化合物。syn -Mo(N-2,6- i -Pr 2 C 6 H 3)(CHCMe 2 Ph)[(S)-Biphen]和syn -Mo(N-2-CF 3 C 6)的X射线晶体学研究H 4)(CHCMe 3)[(S)-Biad](吡啶)证明了双酚盐配体的绝对立体化学。发现新叶叉烯和新戊叉基络合物在溶液中主要具有顺式构象。Mo(N-芳基)(CHR)[Biphen]配合物的[syn] / [anti]平衡常数随芳基酰亚胺配体尺寸的减小而增加,并随着亚烷基取代基的空间体积的减小而减小。通过单参
Kinetic resolution of racemic planar-chiral (eta(5)-1-alkenyl-2-bromocyclopentadienyl)manganese(I) complexes 1 was realized by the molybdenum-catalyzed asymmetric ring-closing metathesis. While vinyl-Cp derivative la was resolved in excellent enantioselectivity with the k(rel) values of up to 127, the selectivity in the ARCM reaction of allyl-Cp derivative 1b was modest (k(rel) = 3.0). ARCM product 2a, which was obtained in an enantiomerically pure form by the two successive ARCM reactions or recrystallization of the enantiomerically enriched products, was found to be a versatile synthetic precursor to various planar-chiral cymantrene derivatives.
Investigations of Reactions between Chiral Molybdenum Imido Alkylidene Complexes and Ethylene: Observation of Unsolvated Base-Free Methylene Complexes, Metalacyclobutane and Metalacyclopentane Complexes, and Molybdenum(IV) Olefin Complexes
作者:W. C. Peter Tsang、Jennifer Y. Jamieson、Sarah L. Aeilts、Kai C. Hultzsch、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1021/om030636+
日期:2004.4.1
molybdacyclobutanes Mo(NR)(*CH2*CH2*CH2)[diolate], olefin complexes Mo(NR)(*CH2CHR)[diolate] (R = H or CMe2Ph), molybdacyclopentane complexes Mo(NR)(*CH2*CH2*CH2*CH2)[diolate], and base-free methylene complexes Mo(NR)(*CH2)[diolate]. We also have crystallographically characterized a molybdenum ethylene complex derived from a biphenolate complex, Mo(N-2,6-Cl2C6H3)(CH2CH2)[rac-Biphen](Et2O).
Molybdenum-Catalyzed Enantioselective Synthesis of Planar-Chiral (η<sup>5</sup>-Phosphacyclopentadienyl)manganese(I) Complexes and Application in Asymmetric Catalysis
Enantioselective desymmetrization of Cs-symmetric (η5-2,5-dialkenylphospholyl)(allyldiphenylphosphine)manganese(I) dicarbonyl complexes 1 was realized by molybdenum-catalyzed asymmetricring-closingmetathesis (ARCM), and the corresponding bridged planar-chiral phosphacymantrene derivatives 2 were obtained in good yields with excellent enantioselectivity. The enantioselectivity of the ARCM reaction
Asymmetric ring-closing metathesis reactions involving achiral and meso substrates
申请人:Massachusetts Institute of Technology
公开号:US06346652B1
公开(公告)日:2002-02-12
A composition and method for the catalytic conversion of a racemic mixture of dienes to a cyclic olefin by a ring-closing metathesis (RCM) reaction are disclosed. The composition, a transition metal complex with an M═C reaction site, contains a bidentate dialkoxide of at least 80% optical purity. Because the M═C reaction site is of a sufficient shape specificity, conferred in part by the dialkoxide of sufficient rigidity and a M═N—R1 site, reacting the composition with a mixture of two enantiomeric dienes results in an olefin metathesis product that has at least a 50% enantiomeric excess of one enantiomer in the mixture. A method is also provided for reacting a composition with a racemic diene mixture to generate a metathesis product that has an enantiomeric excess of at least 50%. Methods are also provided for catalytic enantioselective desymmetrization. One method involves an olefin metathesis reaction with a molecular substrate having a plane of symmetry to form a product free of a plane of symmetry. Another method provides a desymmetrization reaction to occur in the absence of solvent. A method for producing quaternary carbon centers through a desymmetrization reaction is also described.
A composition and method for the catalytic conversion of a racemic mixture of dienes to a cyclic olefin by a ring-closing metathesis (RCM) reaction are disclosed. The composition, a transition metal complex with an M=C reaction site, contains a bidentate dialkoxide of at least 80% optical purity. Because the M=C reaction site is of a sufficient shape specificity, conferred in part by the dialkoxide of sufficient rigidity and an M=N-R1 site, reacting the composition with a mixture of two enantiomeric dienes results in an olefin metathesis product that has at least a 50% enantiomeric excess of one enantiomer in the mixture. A method is also provided for reacting a composition with a racemic diene mixture to generate a metathesis product that has an enantiomeric excess of at least 50%.
TRANSITION METAL CARBENE COMPLEX AND METHOD OF PRODUCING THE SAME
申请人:ZEON CORPORATION
公开号:US20160152645A1
公开(公告)日:2016-06-02
Provided are a transition metal carbene complex represented by the following general formula (1) and a method of producing the same. (In general formula (1), M represents for example a molybdenum atom, R
1
represents for example a C
1
-C-
20
alkyl group optionally having a substituent, L
1
to L
3
each represent a ligand selected for example from a halogen group, R
2
and R
3
each represent for example a hydrogen atom or a C
1
-C
20
alkyl group optionally having a substituent. A represents for example a nitrogen atom, and R
4
to R
7
each represent for example a C
1
-C
20
alkyl group optionally having a substituent.)