Fluorenone Synthesis by Palladacycle-Catalyzed Sequential Reactions of 2-Bromobenzaldehydes with Arylboronic Acids
摘要:
A new, anionic four-electron donor-based (type I) palladacycle-catalyzed sequential reaction of 2-bromobenzaldehydes with arylboronic acids based on the addition reaction, cyclization via C-H activation-oxidation sequence is described. Our study provided an efficient access to a variety of substituted fluorenones/indenofluorenediones from readily available arylboronic acids and 2-bromobenzaldehydes.
carbonylation reaction for the synthesis of fluoren‐9‐ones from 2‐halogenated biphenyls using phenyl formate as a carbon monoxide surrogate was achieved. The combined use of cesium carbonate and o‐anisic acid resulted in a remarkable rate enhancement, where the reaction was complete within 3 min in some cases. Mechanistic studies indicated that the turnover‐limiting step of the reaction was the C−H bond‐cleaving
Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone
作者:Ilya A P Jourjine、Lukas Zeisel、Jürgen Krauß、Franz Bracher
DOI:10.3762/bjoc.17.181
日期:——
Highlysubstituted fluorenones are readily prepared in mostly fair to good yields via metal- and additive-free TBHP-promoted cross-dehydrogenative coupling (CDC) of readily accessible N-methyl-2-(aminomethyl)biphenyls and 2-(aminomethyl)biphenyls. This methodology is compatible with numerous functional groups (methoxy, cyano, nitro, chloro, and SEM and TBS-protective groups for phenols) and was further
通过不含金属和添加剂的 TBHP 促进的易于获得的N-甲基-2-(氨甲基)联苯和 2-(氨甲基)联苯的交叉脱氢偶联 (CDC),可以轻松制备高度取代的芴酮,收率基本上相当到良好。该方法与多种官能团(甲氧基、氰基、硝基、氯以及苯酚的 SEM 和 TBS 保护基团)兼容,并进一步用于天然产物诺比隆的首次全合成。
Norbornene Derivatives-Controlled Palladium-Catalyzed Divergent Synthesis of Dibenzo[<i>a</i>,<i>c</i>]cycloheptenones and Fluorenones from Aryl Iodides and α-Oxocarboxylic Acids
作者:Liwei Zhou、Pengyang Jing、Zhiwei Li、Rui Liu、Jiannan Chen、Guobo Deng、Yun Liang、Yuan Yang
DOI:10.1021/acs.orglett.3c04065
日期:2024.1.26
A palladium-catalyzed divergent cascade decarboxylative annulation of aryliodides and α-oxocarboxylic acids using norbornene (NBE) derivatives as a controlled switch is reported. When NBE is used as a mediator, fluorenones are synthesized with moderate to excellent yields via a Catellani reaction that involves sequential ortho-C–H arylation and ipso-decarboxylative acylation of aryliodides. Employing
据报道,使用降冰片烯(NBE)衍生物作为受控开关,钯催化芳基碘化物和α-氧代羧酸的发散级联脱羧成环。当 NBE 用作介体时,通过 Catellani 反应以中等至优异的产率合成芴酮,该反应涉及芳基碘化物的连续邻位-C–H 芳基化和本身脱羧酰化。使用氧杂降冰片二烯 (ONBD) 代替 NBE 可以通过逆狄尔斯-阿尔德反应组装二苯并[ a , c ]环庚烯酮,而不是释放 ONBD。此外,该方法的合成效用通过产品的多样化得到证明。