权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Lewis acid catalyzed benzannulation

路易斯酸催化苯并环化

基本信息

批准号：
15350052
负责人：
ASAO Naoki
金额：
$ 9.73万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15350052/
关键词：
Lewis acid benzannulation benzo[c]pyrylium ate complex Diels-Alder reaction retro-Diels-Alder reaction enol form gold catalyst copper catalyst

项目摘要

The reaction of o-alkynyl(oxo)benzenes 1 with alkynes 2 in the presence of a catalytic amount of AuCl_3 in (CH_2Cl)_2 at 80℃ gave the [4+2] benzannulation products, naphthyl ketone derivatives 3 and 4, in high yields. When the reaction was carried out using AuBr_3 instead of AuCl_3, the reaction speed was enhanced and the chemical yield was increased. On the other hand, when the reaction was carried out in the presence of a catalytic amount of Cu(OTf)_2 and 1 equivalent of a Bronsted acid, such as CF_2HCO_2H, in (CH_2Cl)_2 at 100℃, the decarbonylated naphthalene products 5 were obtained in high yields. Similarly, the Cu(OTf)_2-H_2O promoted reaction of the enynals 6 with an alkyne 2 afforded the corresponding [4+2] benzannulation products, decarbonylated benzene derivatives 7, in good, yields. Both AuX_<3^-> and Cu(OTf)_2-catalyzed benzannulations proceed most probably through the formation of the benzo[c]pyrylium ate complex 8, the Diels-Alder addition of alkynes 2 to the ate complex, and the resulting bicyclic pyrylium ion intermediate 9. Interestingly, the reaction of enynals 6, including o-alkynylbenzaldehydes 1, and carbonyl compounds 10 in the presence of a catalytic amount of AuBr_3 in 1,4-dioxane at 100℃ gave the functionalized aromatic compounds 3 in high yields. The AuBr_3-catalyzed formal [4+2] benzannulation proceeds most probably through the coordination of the triple bond of 1 to AuBr_3, the formation of pyrylium auric ate complex via the nucleophilic addition of the carbonyl oxygen atom, the reverse electron demand type Diels-Alder addition of the enols, derived from 10, to the auric ate complex, and subsequent dehydration and bond rearrangement. Similarly, the AuBr_3-catalyzed reactions of 1 with acetal compounds afforded the corresponding aromatic compounds in good yields.

邻炔基(氧代)苯1与炔烃2在催化量的AuCl_3存在下在(CH_2Cl)_2中于80℃下反应，高产率地得到[4+2]苯并环化产物萘酮衍生物3和4。当用AuBr_3代替AuCl_3进行反应时，反应速度加快，化学产率增加。另一方面，当反应在催化量的Cu(OTf)_2和1当量布朗斯台德酸(例如CF_2HCO_2H)存在下，在(CH_2Cl)_2中于100℃下进行时，以高收率得到脱羰基萘产物5。类似地，Cu(OTf)_2-H_2O促进烯醛6与炔烃2的反应，得到相应的[4+2]苯并环化产物，即脱羰苯衍生物7，收率良好。 AuX_<3^-> 和 Cu(OTf)_2 催化的苯并环化反应最有可能通过苯并[c]吡喃鎓 ate 络合物 8 的形成、炔烃 2 的 Diels-Alder 加成到 ate 络合物中以及所得的双环吡喃鎓离子中间体 9 进行。有趣的是，烯醛 6 的反应，包括邻炔基苯甲醛1和羰基化合物10在催化量的AuBr_3存在下在1,4-二恶烷中于100℃下以高产率得到官能化芳香族化合物3。 AuBr_3 催化的形式 [4+2] 苯并环化最有可能通过 1 与 AuBr_3 的三键配位进行，通过羰基氧原子的亲核加成形成吡喃鎓金酸络合物，将源自 10 的烯醇进行反向电子需求型狄尔斯-阿尔德加成到金酸络合物，以及随后的反应。脱水和键重排。类似地，AuBr_3 催化的 1 与缩醛化合物的反应以良好的产率提供了相应的芳香族化合物。