Hydrazide‐Catalyzed Polyene Cyclization: Asymmetric Organocatalytic Synthesis of
<i>cis</i>
‐Decalins
作者:Samuel J. Plamondon、Josephine M. Warnica、Dainis Kaldre、James L. Gleason
DOI:10.1002/anie.201911952
日期:2020.1.2
Polyenecyclizations offer rapid entry into terpenoid ring systems. Although enantioselective cyclizations of (E)-polyenes to form trans-decalin ring systems are well precedented, highly enantioselective cyclizations of (Z)-polyenes to form the corresponding cis-decalins have not been reported. Here, we describe the first application of iminium catalysis to the initiation of polyenecyclizations. Ethyl
Synthesis of 4-trifluoromethyl-2<i>H</i>-chromenes <i>via</i> the reaction of 2-(trifluoroacetyl)phenols with vinyltriphenylphosphonium chloride
作者:Alexander S. Golubev、Petr N. Ostapchuk、Tatiana V. Strelkova、Nikolai D. Kagramanov、Kyrill Yu. Suponitsky、Rina U. Takazova、Nikolai D. Chkanikov
DOI:10.1039/d2ob01177h
日期:——
Substituted on the benzene ring 4-CF3-2H-chromenes have been prepared from substituted 2-(trifluoroacetyl)phenols and vinyltriphenylphosphonium chloride according to the Schweizer protocol in moderate to excellent yields. The influence of the type and the position of aromatic ring substituents on yields of 4-CF3-2H-chromenes have been investigated. It has been shown that 4-CF3-2H-chromenes are convenient
根据 Schweizer 协议,在苯环上取代的 4-CF 3 -2 H -色烯由取代的 2-(三氟乙酰基)苯酚和乙烯基三苯基氯化鏻以中等至优异的产率制备。研究了芳环取代基的类型和位置对4-CF 3 -2 H-色烯收率的影响。已经表明4-CF 3 -2 H-色烯是4-CF 3 -香豆素的方便前体。
Photoswitched Stereodivergent Synthesis of Allylic Sulfones
The present Letter demonstrates a photoswitched stereodivergent synthesis of allylic sulfones from sodium sulfinates, triphenylvinylphosphonium chloride, and (hetero)aromatic aldehydes in a single step. Mechanistically, cis-allylic sulfones, generated from the unstabilized ylide intermediates and aldehydes in situ, could be finally converted to trans-allylic sulfones via photochemical isomerization