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.

在80℃中（CH_2CL）_2中催化量的AUCL_3在存在催化量的Aucl_3中，O-Alkynyl（Oxo）苯基1与烷基2的反应得到了[4+2]苯基苯基酮衍生物3和4的反应，以高收益率[4+2]苯基酮衍生物3和4。当反应使用AUBR_3而不是AUCL_3进行反应时，反应速度会提高并增加化学产率。另一方面，当反应在存在催化量的Cu（OTF）_2和1等效的Bronsted酸（例如CF_2HCO_2H）中，在（CH_2CL）_2 in（100）中，脱骨的二苯乙烯产物5以高收益率获得（CH_2CL）_2时。同样，Cu（OTF）_2-H_2O促进了Enynals 6与炔烃2的反应，提供了相应的[4+2]苯并式产物，即脱叠的苯衍生物7，其收益率良好。 AUX_ <3^ - >和Cu（OTF）_2催化的苯济体很可能是通过在复合物8处形成苯并[C] pyrylium，在Ate Complex综合体中添加了Diels-Alker-Alder-Alker-Alker-Alkynes 2向Ate Complefper中添加碱，以及由此产生的生物pyrylium pyrylium imedmediper 9 evertiation nimediper 9。 1和羰基化合物10在1,4-二恶烷中催化量的AUBR_3在100时的催化量，以高产量为官能化的芳族化合物3。 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 nuclear 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.同样，1与乙酰化合物的AUBR_3催化反应以良好的产率提供了相应的芳族化合物。