Enantioselective organocatalytic domino Michael–acetalization–Henry reactions of 2-hydroxynitrostyrene and aldehyde for the synthesis of tetrahydro-6H-benzo[c]chromenones
作者:Bor-Cherng Hong、Prakash Kotame、Ju-Hsiou Liao
DOI:10.1039/c0ob00834f
日期:——
Asymmetric domino Michael–acetalization reactions of 2-hydroxynitrostyrene and aldehydes “on water” followed by oxidation providing the cis-3,4-disubstituted dihydrocoumarins with excellent enantioselectivities (up to >99% ee). The variant with glutaraldehyde underwent a highly stereoselective domino Michael–acetalization–Henry reaction to afford the tetrahydro-6H-benzo[c]chromen-6-ones after the subsequent
不对称多米诺骨牌迈克尔缩醛化反应 2-羟基硝基苯乙烯 和醛“上 水然后进行氧化,使顺式-3,4-二取代的二氢香豆素具有出色的对映选择性(高达> 99%ee)。具有的变体戊二醛进行高度立体选择性的多米诺骨牌Michael-缩醛化-Henry反应,在随后的氧化反应后得到四氢-6 H-苯并[ c ] chromen-6-one。
Stereocontrolled construction of 3H-furo[3,4-b]chromen-1(9H)-one scaffolds via organocatalyzed Michael addition and the following intramolecular dehydration
An efficient approach for the stereocontrolledconstruction of 3H-furo[3,4-b]chromen-1(9H)-oneskeleton has been successfully developed through a sequential Michael addition/intramolecular dehydration strategy. The Michael addition of tetronic acid to 2-((E)-2-nitrovinyl)phenols catalyzed by a bifunctional squaramide derived from L-tert-leucine, and the subsequent intramolecular dehydration promoted
通过顺序迈克尔加成/分子内脱水策略,成功开发了一种立体控制3 H-呋喃并[3,4- b ] chromen-1(9 H)-骨架的有效方法。迈克尔加成特窗酸的2 - ((Ë)-2-硝基乙烯基)苯酚通过衍生自双官能squaramide催化大号-叔-亮氨酸,和由浓硫酸促进了随后的分子内脱水,顺利进行,得到相应的药学上有价值的3 H-呋喃并[3,4- b ] chromen-1(9 H)-one,可接受的收率为ee的79–97%。
Organocatalytic asymmetric Michael/hemiketalization/acyl transfer reaction of 1,3-propanediones with (<i>E</i>)-2-(2-nitrovinyl)phenols
作者:Nimisha Bania、Subhas Chandra Pan
DOI:10.1039/c8ob01771a
日期:——
An organocatalyticasymmetriccascadeMichael/hemiketalization/acyl transfer reaction between (E)-2-(2-nitrovinyl)phenols and 1,3-propanediones is disclosed. A cinchona alkaloid derived bifunctional thiourea catalyst was found to be the most effective for this reaction and provided the desired products in moderate to good yields with good to high enantioselectivities.
Neighboring<i>ortho</i>-Hydroxy Group Directed Catalytic Asymmetric Triple Domino Reactions of Acetaldehyde with (<i>E</i>)-2-(2-Nitrovinyl)phenols
作者:Dhevalapally B. Ramachary、P. Srinivasa Reddy、M. Shiva Prasad
DOI:10.1002/ejoc.201402182
日期:2014.5
neighboring ortho-hydroxy group participation in the pretransition state of enamine- and iminium-based tripledominoreactions for high reactions rates and asymmetric induction. Enantiomerically pure, drug-like chromanes and tetrahydro-6H-benzo[c]chromenes having three to four contiguous stereocenters are synthesized through tripledomino Michael/aldol/oxa-Michael reactions catalyzed by (R)-2-diphenyl[(trim
Metal-Free Diastereo- and Enantioselective Dearomative Formal [3 + 2] Cycloaddition of 2-Nitrobenzofurans and Isocyanoacetate Esters
作者:Adrian Laviós、Amparo Sanz-Marco、Carlos Vila、M. Carmen Muñoz、José R. Pedro、Gonzalo Blay
DOI:10.1021/acs.orglett.2c00427
日期:2022.3.25
The diastereo- and enantioselective dearomative formal [3 + 2] cycloaddition of 2-nitrobenzofurans and α-aryl-α-isocyanoacetate esters provides tricyclic compounds bearing the 3a,8b-dihydro-1H-benzofuro[2,3-c]pyrrole framework with three consecutive stereogenic centers. The reaction was enabled by a cupreine-ether organocatalyst. The reaction products were obtained with almost full diastereoselectivity
2-硝基苯并呋喃和α-芳基-α-异氰基乙酸酯的非对映和对映选择性脱芳香形式[3 + 2]环加成得到带有3 a ,8 b -二氢-1 H -苯并呋喃[2,3- c ]的三环化合物具有三个连续立体中心的吡咯框架。该反应是通过铜醚有机催化剂实现的。获得的反应产物具有几乎完全的非对映选择性,并且对于许多取代的2-硝基苯并呋喃和异氰乙酸酯具有优异的对映体过量。