Hypervalent Iodine Mediated Oxidative Cyclization of o-Hydroxystilbenes into Benzo- and Naphthofurans
摘要:
A new and convenient metal-free cyclization of ortho-hydroxystilbenes into 2-arylbenzofurans and 2-arylnaphthofurans mediated by hypervalent iodine reagents is described. The cyclization products are isolated in good to excellent yields using stoichiometric (diacetoxyiodo)benzene in acetonitrile.
The first highly enantioselective [3 + 2] formal cycloaddition of 1-styrylnaphthols (or phenol) with quinones catalyzed by a chiralphosphoricacid has been reported. A class of trans-2,3-diarylbenzofurans were prepared efficiently (up to 99% yield, >20:1 dr, 99% ee). This organocatalytic procedure allows lowering of the catalyst loading to 0.5 mol % without considerable loss in reactivity and enantioselectivity
A new method for synthesis of benzofurans and naphthofurans from 2-hydroxystilbene derivatives via an intermolecular cyclization is reported in this study with up to 94% isolated yield.
Asymmetric synthesis of triarylsubstituted chromanes with multiple adjacent stereogenic centers is described here. [4+2] formal oxa ‐Diels‐Alder cycloaddition of 1‐styrylnaphthols and in‐situ ‐generated o‐quinone metheides could proceed smoothly in the presence of H 8 ‐BINOL‐type chiral imidodiphosphoric acid as catalyst. This method provides an efficient strategy to construct chiral chromane frameworks
Stereoselective [1 + 1 + 4 + 4] dimerization of 1-styrylnaphthols has been developed by using Selectfluor as the oxidant for the first time. The reaction was compatible with various functional groups, giving a class of ethanodinaphtho[b,f][1,5]dioxocines with novel 3D skeletons. DFT calculations indicate that this method merges an intriguing stereoselective intermolecular 1 + 1 radical coupling to
An efficient method to construct enantioenriched spiro[benzofuro-cyclopenta[1,2-b]indole–indoline] scaffolds via consecutive cyclization is described here. The new scaffolds possess five successive chiral stereogenic centers and two spiroheterocycles. A range of highly enantioenriched scaffolds has been obtained with up to 93% yield, 99% ee and >19 : 1 d.r. catalyzed by Brønsted acid catalysts.
本文描述了一种通过连续环化来构建对映体富集的螺[苯并呋喃-环戊五[1,2 - b ]吲哚-吲哚啉]支架的有效方法。新的支架具有五个连续的手性立体发生中心和两个螺杂环。已经获得了一系列高度对映体富集的支架,其通过布朗斯台德酸催化剂催化的产率高达93%,ee为99%,dr> 19:1 dr。