catalytic methods for the oxidative furan-recyclizations remain scarcely investigated. Given this, we report a means of manganese-catalyzed oxidations of furan with low loading, achieving the Achmatowiczrearrangement in the presence of hydrogen peroxide as an environmentally benign oxidant under mild conditions with wide functional group compatibility.
additions to organic carbonyls. Aryl additions of AlArEt2(THF) to aldehydescatalyzed by the titanium(IV) complex of (R)-H8−BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing
一系列AlArEt 2(THF)(Ar = Ph(1a),4-MeC 6 H 4(1b),4-MeOC 6 H 4(1c),4-Me 3 SiC 6 H 4(1d),2-由AlEt 2 Br(THF)与ArMgBr的反应合成萘基(1e)。在CDCl 3溶液中,1 H NMR光谱表明,AlArEt 2(THF)化合物以AlAr x Et 3- x(THF)(x= 0、1、2或3)。发现AlArEt 2(THF)化合物是不对称芳基加成到有机羰基化合物中的优良化合物,并且是原子经济的试剂。由(R)-H 8 -BINOL的钛(IV)络合物催化的AlArEt 2(THF)芳基加成醛的反应效率高,反应时间短至1 h,从而以高收率提供芳基加成产物作为独家产物或主要产物以及高达98%ee的优异对映选择性。尽管乙醛中乙醛的添加量很小,但这项研究表明,增加AlArEt 2的含量(THF)从1.2到1.4或到1
Unprecedented Reactivity of γ‐Amino Cyclopentenone Enables Diversity‐Oriented Access to Functionalized Indoles and Indole‐Annulated Ring Structures
作者:Chenna Jagadeesh、Biplab Mondal、Sourav Pramanik、Dinabandhu Das、Jaideep Saha
DOI:10.1002/anie.202016015
日期:2021.4.12
indole derivatives, which is developed in the current study. Herein, a vast range of C3/N‐indolyl enones and indole alkaloid‐like compound were accessed in excellent yields (up to 99 %) and selectivity through a one‐pot operation. The mechanism most likely involves an unprecedented trait of Piancatelli‐type rearrangement where influence of the gem‐diaryl group appeared crucial.
A new synthesis of 5-methylene-2(5H)-furanone derivatives
作者:Roberto Antonioletti、Maurizio D'Auria、Antonella De Mico、Giovanni Piancatelli、Arrigo Scettri
DOI:10.1016/s0040-4020(01)88810-4
日期:1984.1
5-methylene-2(5H)-furanonederivatives are easily obtained by treatment of tertiary 2-furylcarbinols with pyridinium dichromate in dimethylformamide solution. Through this procedure, a natural product, the thiophene lactone isolated from Chamaemelum Nobile L., has been synthesized.
The authors acknowledge financial support from the Spanish Ministerio de Ciencia y Tecnologia (MCYT) (project numbers CTQ2007-65218/BQU and CTQ2011-24151), Consolider Ingenio 2010 (grant number CSD2007-00006), and Generalitat Valenciana (G. V. PROMETEO/2009/039 and FEDER). B. M. thanks the European Commision for a Marie Curie Career Integration Grant. E. F.-M. thanks the Ministerio de Educacion y Ciencia