The photochemically initiated dehydro-Diels-Alder (PDDA) reaction is an efficient and versatile method for the prepa- ration of biaryls. The ring closure may take place both inter- and in- tramolecularly, of which the intramolecular variant is more productive from the preparative point of view. A variety of linkers can be employed to connect the ynone moiety, which acts as the chromophore, with another
C−H Bond Activation for the Synthesis of Heterocyclic Atropisomers Yields Hedgehog Pathway Inhibitors
作者:Gang Shan、Jana Flegel、Houhua Li、Christian Merten、Slava Ziegler、Andrey P. Antonchick、Herbert Waldmann
DOI:10.1002/anie.201809680
日期:2018.10.22
pronounced bioactivity, and methods for their efficient synthesis have gained widespread attention. However, enantioselective synthesis of axially chiral 4‐arylisoquinolones by means of C−Hactivation has not been reported to date. Described here is a rhodium (III)‐catalyzed C−Hbondactivation and annulation for the atroposelective synthesis of axially chiral 4‐arylisoquinolones. The method employs
An insecticidal composition comprising, in admixture with an agriculturally acceptable carrier, an insecticidally effective amount of a compound of the formula: ##STR1## wherein R, R.sup.1, R.sup.2, R.sup.3, R.sup.7, R.sup.8, m, n, and p are as defined herein, and agriculturally acceptable salts thereof, and methods of using the same.
Bromotrimethylsilane (TMSBr)-promoted intramolecular cyclization of (o-arylethynyl)benzylethers to form 1H-isochromenes at room temperature is reported. Further studies indicated that vinyl carbocations are the reaction intermediates which are stabilized by the conjugated aryl groups. Thus, O-addition of benzylethers/tetrahydropyrans to alkynes was achieved under metal-free, acidic conditions. These
报道了溴代三甲基硅烷 (TMSBr) 促进的 ( o -arylethynyl) 苄基醚在室温下分子内环化形成 1 H-异色烯。进一步的研究表明,乙烯基碳阳离子是由共轭芳基稳定的反应中间体。因此,在无金属、酸性条件下实现了苄基醚/四氢吡喃与炔烃的O-加成。这些反应条件与炔基普林斯反应相容;因此,使用一锅法直接由炔基苯甲醛和炔醇生产1 H-异色烯。
The Photo-Dehydro-Diels-Alder Reaction: An Efficient Route to Naphthalenes
photochemical route to naphthalenes is presented. The [4+2] cycloaddition takes place between 3-arylynones and arylacetylenes, in which these moieties may be located intwo molecules (intermolecular PDDA, 1) or in the same molecule (intramolecular PDDA, 5 and 9). Especially the latter approach is attractive from a preparative point of view and permits a straightforward access to highly functionalized naphthalenes