Bis(oxazoline) and Bis(oxazolinyl)pyridine Copper Complexes as Enantioselective Diels−Alder Catalysts: Reaction Scope and Synthetic Applications
作者:David A. Evans、David M. Barnes、Jeffrey S. Johnson、Thomas Lectka、Peter von Matt、Scott J. Miller、Jerry A. Murry、Roger D. Norcross、Eileen A. Shaughnessy、Kevin R. Campos
DOI:10.1021/ja991191c
日期:1999.8.1
the use of this chiral catalyst in more complex Diels−Alder processes, are described. Similarly, the cationic coppercomplex 9a, [Cu((S,S)-t-Bu-pybox)](SbF6)2, is effective in the Diels−Alder reactions of monodentate acrolein dienophiles while the closely related complex, 9d [Cu((S,S)-Bn-pybox)](SbF6)2, is the preferred Lewis acid catalyst for acrylate dienophiles in reactions with cyclopentadiene.
Swapped selectivities: The use of tailor‐made catalysts results in anomalous endo/exo selectivities and high enantioselectivities in the Diels–Alder reactions of cyclopentadiene with different acroleins (see scheme). These supramolecular catalysts are prepared in situ from chiral diols, arylboronic acid, and tris(pentafluorophenyl)borane, and can discriminate the re/si face of the dienophile as well
BBr3-chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Brønsted acid (LBA) catalysts for promoting the enantioselective Diels-Alder (DA) reaction of α-substituted acroleins and α-CF3 acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydropyridines gave the corresponding optically active isoquinuclidines with high enantioselectivities
Catalytic enantioselective Diels-Alder reactions using titanium complexes of cis-N-sulfonyl-2-amino-1-indanols
作者:E.J. Corey、Thomas D. Roper、Kazuaki Ishihara、Georgios Sarakinos
DOI:10.1016/s0040-4039(00)61343-6
日期:1993.1
A titaniumcomplex derived from (1R, 2S)-N-(2,4,6-trimethylbenzenesulfonyl)-2-amino-1-indanol catalyzes the Diels-Alder reaction of 2-bromoacrolein and cyclopentadiene with 96.5:3.5 enantioselectivity. A new and efficient synthesis of 2-amino-1-indanol (6) contributes to the potential of this methodology.
large rate differences on variation of the anion are all characteristics of the new Ru Lewisacid [CpRu((S,S)-biphop-F)]+ (biphop-F=(C6 F5 )2 POCH2 (Ph)CH2 (Ph)OP(C6 F5 )2 ). The structure of complex 1 (L=methacrolein, Y=SbF6 ) provides evidence for a cooperative binding of the dienophile by both the Lewisacid and the anion.
易产生,在室温下溶液中稳定,在Diels-Alder反应中具有高对映选择性,有效的催化剂回收率以及阴离子变化率大的差异都是新的Ru Lewis酸[CpRu((S,S)- biphop-F)] +(biphop-F =(C 6 F 5)2 POCH 2(Ph)CH 2(Ph)OP(C 6 F 5)2)。配合物1的结构(L =甲基丙烯醛,Y = SbF 6)提供了路易斯酸和阴离子对亲二烯体的协同结合的证据。