Tertiary and Quaternary Carbon Formation via Gallium-Catalyzed Nucleophilic Addition of Organoboronates to Cyclopropanes
作者:Truong N. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.7b03349
日期:2018.1.5
via homoconjugate addition of organoboron nucleophiles to diester- and ketone-functionalized cyclopropanes. Electron donor group cyclopropane substituents were not needed, allowing electron-deficient aryl, alkenyl, alkyl, and hydrogen-substituted cyclopropanes to be used. The catalytic conditions were compatible with alkenyl, alkynyl, and arylnucleophiles, including ortho-substituted aromatics, to
Formal Insertion of Thioketenes into Donor–Acceptor Cyclopropanes by Lewis Acid Catalysis
作者:André U. Augustin、Marius Busse、Peter G. Jones、Daniel B. Werz
DOI:10.1021/acs.orglett.7b03961
日期:2018.2.2
Donor–acceptorcyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones as surrogates for disubstituted thioketenes. A broad scope of 2-substituted tetrahydrothiophenes with a semicyclic double bond was obtained under mild conditions with high functional group tolerance and in excellent yield. A sequence of a formal [3 + 2]-cycloaddition followed by the subsequent release of
(3+2)-Cycloaddition of Donor–Acceptor Cyclopropanes with Thiocyanate: A Facile and Efficient Synthesis of 2-Amino-4,5-dihydrothiophenes
作者:Daniel B. Werz、Anu Jacob、Philip Barkawitz、Ivan A. Andreev、Nina K. Ratmanova、Igor V. Trushkov
DOI:10.1055/a-1385-2385
日期:2021.6
An easy and efficient route to obtain 2-amino-4,5-dihydrothiophenes is presented. A formal (3+2)-cycloaddition of donor–acceptor cyclopropanes and ammonium thiocyanate catalyzed by Yb(OTf)3 delivers the desired products in good to excellent yields. A broad range of functional groups is tolerated during this process.
(4 + 3)-Cycloaddition of Donor–Acceptor Cyclopropanes with Thiochalcones: A Diastereoselective Access to Tetrahydrothiepines
作者:André U. Augustin、J. Luca Merz、Peter G. Jones、Grzegorz Mlostoń、Daniel B. Werz
DOI:10.1021/acs.orglett.9b03623
日期:2019.12.6
tetrahydrothiepines using donor-acceptorcyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewisacidcatalyzed formal (4 + 3)-cycloaddition reaction with donor-acceptorcyclopropanes as three-atom building blocks. Under mild conditions various tetrahydrothiepines were synthesized in good yields in a stereospecific reaction with high functional group tolerance
Reactions of Donor-Acceptor Cyclopropanes with Naphthoquinones: Redox and Lewis Acid Catalysis Working in Concert
作者:Alexander Lücht、Lukas J. Patalag、André U. Augustin、Peter G. Jones、Daniel B. Werz
DOI:10.1002/anie.201703732
日期:2017.8.21
trigger the ring-opening of the three-membered ring with formation of a new C−C bond. Treatment of these products with base under oxidative conditions resulted—through loss of methyl formate—in cyclopentannulated products with fully conjugated π systems exhibiting intensive absorptions in the visible range.