Cobalt-Catalyzed Divergent Cycloadditions of Alkynes with Conjugated Dienes Yielding 3-Vinylcyclobutenes, Bicyclo[3.1.0]hexenes, and Cyclohexa-1,4-dienes
Cobalt-Catalyzed Divergent Cycloadditions of Alkynes with Conjugated Dienes Yielding 3-Vinylcyclobutenes, Bicyclo[3.1.0]hexenes, and Cyclohexa-1,4-dienes
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钴催化的炔烃与共轭二烯的发散环加成反应生成 3-乙烯基环丁烯、双环[3.1.0]己烯和环己-1,4-二烯
DOI：
10.1021/acs.orglett.2c03108
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发表时间：
2022
期刊：
影响因子：
5.2
通讯作者：
Hirano Masafumi
中科院分区：
文献类型：
--
作者：
Tomita Yusuke;Haraguchi Naoto;Kiyota Sayori;Komine Nobuyuki;Hirano Masafumi
传统的钴催化剂体系仍有未被发现的反应性。根据所使用的叔膦和底物的不同，使用CoBr2/叔膦/锌/锌的催化体系可以催化内炔与共轭双烯的分歧环加成反应，生成3-烯基环-1-烯、双环[3.1.0]己烯和环己二烯。3-己炔(1a)与1-(4-甲氧基苯基)丁二烯(2a)在CH2Cl2中以[CoBr2(PPh_3)_2]/Zn/ZnI_2为催化剂在室温下反应生成[2+2]环加成产物(E)-2-(2，3-diethylcyclobut-2-ene-1-yl)vinyl-4-methoxybenzene(3AA)。当以[CoBr2(Dppp)]/Zn/ZnI2为催化剂时，以6-(4-methoxyphenyl)-2，3-diethylbicyclo[3.1.0]hex-2-ene(4AA)为主的双环化合物的产率为77%。CoBr2/dppe/Zn/ZnI2体系可进行[2+4]环加成反应，生成以3-(4-苯甲酰基)-1，2-二乙基环己二烯(5AA)为主的产物，产率为38%。所用配体的咬合角对这种催化多样性有很大贡献。
A traditional cobalt catalyst system still contains undiscovered reactivity. Depending on the tertiary phosphines and substrates used, the catalytic system using CoBr2/tertiary phosphine/Zn/ZnI2catalyzes divergent cycloadditions of internal alkynes with conjugated dienes, yielding 3-alkenylcyclobut-1-enes, bicyclo[3.1.0]hexenes, and cyclohexa-1,4-dienes. A [CoBr2(PPh3)2]/Zn/ZnI2-catalyzed reaction of 3-hexyne (1a) with 1-(4-methoxyphenyl)butadiene (2a) at room temperature in CH2Cl2exclusively produces a [2 + 2] cycloaddition product (E)-2-(2,3-diethylcyclobut-2-ene-1-yl)vinyl-4-methoxybenzene (3aa). When [CoBr2(dppp)]/Zn/ZnI2is used as a catalyst, a bicyclic compound 6-(4-methoxyphenyl)-2,3-diethylbicyclo[3.1.0]hex-2-ene (4aa) is dominantly formed in a 77% yield. The CoBr2/dppe/Zn/ZnI2system can undergo a [2 + 4] cycloaddition to yield 3-(4-anisyl)-1,2-diethylcyclohexa-1,4-diene (5aa) as the dominant product in 38% yield. The bite angles of the ligands used contribute significantly to this catalytic diversity.