[EN] A SINGLE STEP ENANTIOSELECTIVE PROCESS FOR THE PREPARATION OF 3-SUBSTITUTED CHIRAL PHTHALIDES [FR] PROCÉDÉ ÉNANTIOSÉLECTIF EN UNE SEULE ÉTAPE POUR LA PRÉPARATION DE PHTALIDES CHIRAUX 3-SUBSTITUÉS
A tandem Aldol-Grob reaction of ketones with aromatic aldehydes
作者:George W. Kabalka、David Tejedor、Nan-Sheng Li、Rama R. Malladi、Sarah Trotman
DOI:10.1016/s0040-4020(98)00976-4
日期:1998.12
Aromatic aldehydes react with ketones to produce(E)-1-aryl-1-alkenes via a tandem Aldol-Grob cleavage reaction sequence. The reaction, initiated by boron trifluoride, also produces a carboxylic acid fragment.
Asymmetric copper-catalyzed allylic alkylation between allyl bromides and alkyl Grignard reagents using a P-chiral monophosphorus ligand is described. A range of terminal olefins bearing tertiary or quaternary carbon centers were formed in good branched/linear selectivities and excellent enantioselectivities at copper loadings as low as 0.5 mol %.
ALKENES AS ALKYNE EQUIVALENTS IN RADICAL CASCADES TERMINATED BY FRAGMENTATIONS
申请人:The Florida State University Research Foundation, Inc.
公开号:US20160347778A1
公开(公告)日:2016-12-01
Disclosed are methods for rerouting radical cascade cyclizations by using alkenes as alkyne equivalents. The reaction sequence is initiated by a novel 1,2 stannyl shift which achieves chemo- and regioselectivity in the process. The radical “hopping” leads to the formation of the radical center necessary for the sequence of selective cyclizations and fragmentations to follow. In the last step of the cascade, the elimination of a rationally designed radical leaving group via β-C—C bond scission aromatizes the product without the need for external oxidant. The Bu
3
Sn moiety, which is installed during the reaction sequence, allows further functionalization of the product via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of enynes into extended polycyclic structures of tunable dimensions.
A Visible-Light-Mediated Oxidative CN Bond Formation/Aromatization Cascade: Photocatalytic Preparation of N-Arylindoles
作者:Soumitra Maity、Nan Zheng
DOI:10.1002/anie.201205137
日期:2012.9.17
Just add light and air: Structurally diverse N‐arylindoles can be prepared from readily prepared o‐styryl anilines through visible‐light photocatalysis. The reaction, which is conducted open to air, is mediated by [Ru(bpz)3](PF6)2 (bpz=2,2′‐bipyrazine) and involves both CNbondformation and aromatization (see scheme). Using suitably substituted substrates, a 1,2‐carbon shift can be also incorporated
只需添加光和空气:可以通过可见光光催化从容易制备的邻苯乙烯基苯胺制备结构多样的N-芳基吲哚。该反应在空气中进行,由 [Ru(bpz) 3 ](PF 6 ) 2 (bpz=2,2′-联吡嗪)介导,涉及 C N 键形成和芳构化(见方案)。使用适当取代的底物,1,2-碳转移也可以纳入该级联反应中。
Design of Leaving Groups in Radical CC Fragmentations: Through-Bond 2c-3e Interactions in Self-Terminating Radical Cascades
作者:Sayantan Mondal、Brian Gold、Rana K. Mohamed、Igor V. Alabugin
DOI:10.1002/chem.201402843
日期:2014.7.7
Radicalcascades terminated by β‐scission of exocyclic CC bonds allow for the formation of aromatic products. Whereas β‐scission is common for weaker bonds, achieving this reactivity for carbon–carbon bonds requires careful design of radicalleavinggroups. It has now been found that the energetic penalty for breaking a strong σ‐bond can be compensated by the gain of aromaticity in the product and