Enantioselective Diels−Alder Reaction Using Chiral Mg Complexes Derived from Chiral 2-[2-[(Alkyl- or 2-[2-[(Arylsulfonyl)amino]phenyl]-4-phenyl-1,3-oxazoline
complexes derived from (R)-2-[2-[(alkyl- or (R)-2-[2-[(arylsulfonyl)amino]phenyl]-4-phenyl-1,3-oxazolines and methylmagnesium iodide were found to be efficient Lewis acid catalysts for the Diels-Alder reaction of 3-alkenoyl-1,3-oxazolidin-2-one with cyclopentadiene. Chiral ligands were easily prepared from readily available D-phenylglycinol in good yields. The reaction of 3-acryloyl-1,3-oxazolidin-2-one
The Role of Achiral Pyrazolidinone Templates in Enantioselective Diels−Alder Reactions: Scope, Limitations, and Conformational Insights
作者:Mukund P. Sibi、Levi M. Stanley、Xiaoping Nie、Lakshmanan Venkatraman、Mei Liu、Craig P. Jasperse
DOI:10.1021/ja066425o
日期:2007.1.1
were also observed in reactions of 7d with chiralLewis acids derived from relatively small chiralligands, suggesting the pyrazolidinone templates are capable of relaying stereochemical information from the ligand to the reaction center. Lewis acids capable of adapting square planar geometries, such as Cu(OTf)2, Cu(ClO4)2, and Pd(ClO4)2, were found to be particularly effective at providing high selectivities
Chiral 2,2′-Binaphthyldiimine–Nickel(II) Complexes as Lewis Acid Catalysts for Enantioselective Diels–Alder Reactions
作者:Hiroyuki Suga、Akikazu Kakehi、Masashi Mitsuda
DOI:10.1246/bcsj.77.561
日期:2004.3
The preparation and application of a novel class of chiral Lewisacid catalysts based on chiral 2,2′-binaphthyldiimine ligands are described. Among the binaphthyldiimine–metal complexes tested, N,N...
Transition-Metal Aqua Complexes of 4,6-Dibenzofurandiyl-2,2‘-bis(4-phenyloxazoline). Effective Catalysis in Diels−Alder Reactions Showing Excellent Enantioselectivity, Extreme Chiral Amplification, and High Tolerance to Water, Alcohols, Amines, and Acids
作者:Shuji Kanemasa、Yoji Oderaotoshi、Shin-ichi Sakaguchi、Hidetoshi Yamamoto、Junji Tanaka、Eiji Wada、Dennis P. Curran
DOI:10.1021/ja973519c
日期:1998.4.1
from nickel(II) perchlorate hexahydrate has an octahedral structure with three aqua ligands, and it can be isolated and stored for months without loss of catalytic activity. Iron(II), cobalt(II), copper(II), and zinc(II) complexes are similarly active. The absoluteconfiguration induced in the reaction can be readily predicted on the basis of the C2-symmetric structure of the complexes as well as the
阳离子水配合物由反式螯合三齿配体 (R,R)-4,6-二苯并呋喃二基-2,2'-双(4-苯基恶唑啉) (DBFOX/Ph) 和各种过渡金属 (II) 制备高氯酸盐。这些配合物是环戊二烯与 3-烯酰基-2-恶唑烷酮亲二烯体的 Diels-Alder 反应的有效催化剂,并显示出优异的对映选择性。由六水合高氯酸镍 (II) 制备的活性催化剂配合物具有八面体结构和三个水配体,可以分离和储存数月而不会损失催化活性。铁 (II)、钴 (II)、铜 (II) 和锌 (II) 配合物具有类似的活性。根据配合物的 C2 对称结构以及底物配合物的简单结构,可以很容易地预测反应中诱导的绝对构型。由 Ni(II) 或 Zn(II) 高氯酸盐制备的水络合物在 Diels-Alder 反应中产生高效的手性放大。使用 DBFOX/Ph 配体...
Synthesis of dipeptides containing α-substituted amino acids; their use as chiral ligands in Lewis-acid-catalyzed reactions
作者:Bernard Kaptein、Vania Monaco、Quirinus B. Broxterman、Hans E. Schoemaker、Johan Kamphuis
DOI:10.1002/recl.19951140417
日期:——
Ochrobactrum anthropi NCIMB 40321, was used in the synthesis of dipeptidescontainingα-substitutedaminoacids. The 2-hydroxynaphthalene-1-carboxaldehyde Schiff bases of the dipeptides (1 and 2) were tested as Ti(IV) and Al(III) complexes in asymmetric Lewis-acid-catalyzedreactions. Only the Al(III) complex of 2 showed moderate enantioselectivity in the cyanation reaction of benzaldehyde with TMS-CN.