The diazo route to diazonamide A: studies on the tyrosine-derived fragment
作者:Francine N. Palmer、Franck Lach、Cyril Poriel、Adrian G. Pepper、Mark C. Bagley、Alexandra M. Z. Slawin、Christopher J. Moody
DOI:10.1039/b510653b
日期:——
the original structure of diazonamide A was prepared in eight steps from N-Z-tyrosine tert-butyl ester. Iodination, O-protection and Stille coupling gave the cinnamyl alcohol 25, converted via the bromide into the allyl aryl ether 27. Subsequent Claisen rearrangement and oxidative cleavage of the alkene gave the lactol 29, converted into the desired benzofuranone 31. The revision in the structure of
Visible‐Light‐Mediated Heterocycle Functionalization via Geometrically Interrupted [2+2] Cycloaddition
作者:Mihai V. Popescu、Aroonroj Mekereeya、Juan V. Alegre‐Requena、Robert S. Paton、Martin D. Smith
DOI:10.1002/anie.202009704
日期:2020.12.14
cyclization in the triplet excited state to yield a 1,4‐diradical; intersystem crossing leads preferentially to the closed shell singlet zwitterion. This is geometrically restricted from undergoing recombination to yield a cyclobutane by the planarity of the amide substituent. A prototropic shift leads to the observed bicyclic products in what can be viewed as an interrupted [2+2] cycloaddition.
Electrochemical oxidative <i>Z</i>-selective C(sp<sup>2</sup>)–H chlorination of acrylamides
作者:James Harnedy、Mishra Deepak Hareram、Graham J. Tizzard、Simon J. Coles、Louis C. Morrill
DOI:10.1039/d1cc05824j
日期:——
An electrochemical method for the oxidative Z-selective C(sp2)–H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was
The compounds 2-Aryl-3-amino-1-butanol derivatives of the formula ##STR1## wherein R represents hydrogen or acyl; R.sup.1 and R.sup.2 each independently represents hydrogen, phenyl lower alkyl, or lower alkoxy substituted phenyl lower alkyl, or both R.sup.1 and R.sup.2 are lower alkyl; and their pharmaceutically acceptable acid salts. The compounds are crystalline solids or liquids which, having two asymmetry centers, can be obtained in their stereoisomeric forms as racemic mixtures or in their optically active forms. The compounds have cardiovascular activity as coronary dilators. The compounds can be prepared by reacting an .alpha.-arylcrotonate with ammonia or with an amine followed by hydrogenation of the carbalkoxy group to give the corresponding butanol. The butanols are acylated in usual ways to give the compounds of formula (I) wherein R represents an acyl group.
We herein report α-arylsulfonyloxyacrylates as a kind of useful and attractive O-centered electrophiles for Suzuki cross-coupling reactions. A range of α-(hetero)aryl substituted acrylates has been prepared via the palladium-catalysed C–C cross-coupling reactions between potassium (hetero)aryltrifluoroborates and α-arylsulfonyloxyacrylates. Moreover, α-arylsulfonyloxyacrylate could also react with