An unprecedented Lewis acidcatalyzed, protection-free, and high-efficiency synthesis of valuable 3,4-dihydro-2H-2,4-methanochromans via cycloaddition of propargylic alkynols with 2-vinylphenol is described. This cycloaddition protocol, which tolerates a wide variety of functional groups, provides practical, versatile, and atom-economical access to a new class of appealing bridged-ring products in
本文描述了一种空前的路易斯酸,其通过炔丙基炔醇与2-乙烯基苯酚的环加成反应,催化了有价值的3,4-二氢-2 H -2,4-甲烷二甲基苯并没有保护性地进行了高效合成。该环加成方案可耐受多种官能团,以令人满意的收率提供实用,通用且经济实惠的途径来获得新型的有吸引力的桥环产品。与报道的桥环骨架合成反应条件相比,目前的反应条件是中性,温和且没有任何添加剂。
Cp*Co(<scp>iii</scp>)-Catalyzed oxidative [5+2] annulation: regioselective synthesis of 2-aminobenzoxepines <i>via</i> C–H/O–H functionalization of 2-vinylphenols with ynamides
作者:Xiang-Lei Han、Xu-Ge Liu、E Lin、Yunyun Chen、Zhuangzhong Chen、Honggen Wang、Qingjiang Li
DOI:10.1039/c8cc06807k
日期:——
A Cp*Co(III)-catalyzed [5+2] C–H annulation reaction of 2-vinylphenols with ynamides was developed. The reaction led to the efficient synthesis of valuable 2-aminobenzoxepines in high regioselectivity. Mild reaction conditions, good functional group tolerance, and moderate to good yields were observed. The synthetic utility was demonstrated by a gram-scale synthesis and further transformations of the
propargyl carbonates have been developed by using two O-containing functional groups as the traceless assisting groups (AGs). The experimental investigations together with the density functional theory (DFT) calculations revealed that this transformation involves the free OH-directed cleavage of one terminal C–H bond of the alkenyl moiety and regioselective alkyne insertion, followed by OBoc-promoted intramolecular
Oxidative Inter-/Intermolecular Alkene Diamination of Hydroxy Styrenes with Electron-Rich Amines
作者:Michael W. Danneman、Ki Bum Hong、Jeffrey N. Johnston
DOI:10.1021/acs.orglett.5b01177
日期:2015.5.15
Doubly intermolecularalkenediamination is achieved with electron-rich, terminal alkenes through the use of a hypervalent iodine (PhI(OAc)2) reagent, iodide, and electron-rich amines. Mono- and disubstituted amines combine with electron-rich alkenes, particularly o-hydroxystyrenes, to achieve the greatest level of generality. This operationally straightforward protocol, unreliant on conventional metal-based
Phenols were vinylated at the ortho-position with ethyne in the presence of SnCl(4)-Bu(3)N reagent. The reaction was applicable to phenols possessing either electron-donating or electron-withdrawing groups. 2,6-Divinylphenols were synthesized under modified conditions. A reaction mechanism involving carbostannylation of alkynyltin and phenoxytin was discussed.