ABSTRACT
In this work we have found that a BODIPY can be used as an electron withdrawing group for the activation of double bonds in asymmetric catalysis. The synthesis of cyclohexyl derivatives containing a BODIPY unit can easily be achieved via trienamine catalysis. This allows a new different asymmetric synthesis of BODIPY derivatives and opens the door to future transformation of this useful fluorophore. In addition, the Quantum Chemistry calculations and mechanistic studies provide insights into the role of BODIPY as an EWG.
ABSTRACT
The organocatalytic enantioselective synthesis of highly functionalized hydroisoquinolines by trienamine-mediated [4+2]-cycloaddition/nucleophilic ring-closing reaction cascade sequence of cyanoacrylamides with 2,4-dienals is presented. The corresponding cycloadducts are formed in high yields and excellent stereoselectivities. Moreover, a series of transformations demonstrate the synthetic application of the obtained hydroisoquinolines.
Subject(s)
Acrylamides/chemistry , Aldehydes/chemistry , Cycloaddition Reaction/methods , Isoquinolines/chemical synthesis , Catalysis , Crystallography, X-Ray , Isoquinolines/chemistry , Molecular Structure , StereoisomerismABSTRACT
The synthesis of optically active, carboannulated dihydronaphthoquinone and naphthoquinone derivatives with up to four stereogenic centers is demonstrated by H-bond-directed, trienamine-mediated [4 + 2]-cycloadditions. The outcome of the reaction between 2,4-dienals and 1,4-naphthoquinones is controlled by the substituent in the 2-position of the 1,4-naphthoquinone. In the case of sterically demanding 2-substituted derivatives, dihydronaphthoquinones are obtained. However, when a hydrogen atom is present in the 2-position, a subsequent oxidation of the initially formed cycloadducts occurs yielding naphthoquinones.
