A versatile catalyst system for enantioselective synthesis of 2-substituted 1,4-benzodioxanes
作者:Eugene Chong、Bo Qu、Yongda Zhang、Zachary P. Cannone、Joyce C. Leung、Sergei Tcyrulnikov、Khoa D. Nguyen、Nizar Haddad、Soumik Biswas、Xiaowen Hou、Katarzyna Kaczanowska、Michał Chwalba、Andrzej Tracz、Stefan Czarnocki、Jinhua J. Song、Marisa C. Kozlowski、Chris H. Senanayake
DOI:10.1039/c8sc05612a
日期:——
We report the synthesis of enantiomerically enriched 1,4-benzodioxanes containing alkyl, aryl, heteroaryl, and/or carbonyl substituents at the 2-position. The starting 1,4-benzodioxines were readily synthesized via ring closing metathesis using an efficient nitro-Grela catalyst at ppm levels. Excellent enantioselectivities of up to 99:1 er were obtained by using the versatile catalyst system [Ir(c
The Preparation and Coupling Reactions of 2-Bromo-1,4-benzodioxin. A Simple Synthesis of 2-(1-Alkenyl)-, 2-Alkyl-and 2-Aryl-1,4-benzodioxins
作者:Thomas V. Lee、Alistair J. Leigh、Christopher B. Chapleo
DOI:10.1055/s-1989-27201
日期:——
2-Bromo-1,4-benzodioxin is prepared by dehydrobromination of 2,3-dibromo-2,3-dihydro-1,4-benzodioxin with base. It is converted into 2-alkyl-, 2-(1-alkenyl)-, and 2-aryl-1,4-benzodioxins by reaction with the respective Grignard reagents or by conversion into 2-(bromomagnesio)-1,4-benzodioxin and reaction of this Grignard reagent with alkyl, 1-alkenyl, or aryl halides.