Tandem Nucleophilic Addition/Oxa-Michael Reaction for the Synthesis of<i>cis</i>-2,6-Disubstituted Tetrahydropyrans
作者:Santosh J. Gharpure、J. V. K. Prasad、Kalisankar Bera
DOI:10.1002/ejoc.201402199
日期:2014.6
A Lewis acid catalyzed tandem nucleophilic addition/oxa-Michaelreaction was developed for the synthesis of cis-2,6-disubstituted tetrahydropyran (THP) derivatives in good yields with excellent diastereoselectivities. The strategy was successfully used in the construction of THP derivatives with three stereocenters in a highly stereoselective fashion.
Rh(<scp>iii</scp>)-catalyzed diastereoselective C–H bond addition/cyclization cascade of enone tethered aldehydes
作者:Jeffrey A. Boerth、Jonathan A. Ellman
DOI:10.1039/c5sc04138d
日期:——
The Rh(III)-catalyzed cascade addition of a C–H bond across alkene and carbonyl π-bonds is reported. The reaction proceeds under mild reaction conditions with low catalyst loading. A range of directing groups were shown to be effective as was the functionalization of alkenyl in addition to aromatic C(sp2)–H bonds. When the enone and aldehyde electrophile were tethered together, cyclic β-hydroxy ketones
报道了Rh( III ) 催化的 C-H 键在烯烃和羰基 π-键上的级联加成。该反应在温和的反应条件和低催化剂负载下进行。一系列导向基团被证明是有效的,除了芳香族 C(sp 2 )–H 键之外,烯基的官能化也是如此。当烯酮和醛亲电体连接在一起时,得到具有三个连续立体中心的环状β-羟基酮,具有高非对映选择性。醛和亚胺亲电子试剂都证明了分子间三组分级联反应。此外,报告了第一个阳离子 Cp*Rh( III ) 烯醇化物的 X 射线结构,其原子间距离与 η 3结合烯醇化物一致。
Asymmetric Sequential Aza-Diels-Alder and<i>O</i>-Michael Addition: Efficient Construction of Chiral Hydropyrano[2,3<i>-b</i>]pyridines
作者:Xiang Yin、Qingqing Zhou、Lin Dong、Yingchun Chen
DOI:10.1002/cjoc.201200942
日期:2012.11
An asymmetric aza‐Diels‐Alder and O‐Michael addition sequence has been developed to construct chiral hydropyrano[2,3‐b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N‐Ts‐1‐aza‐1,3‐butadienes and aliphatic aldehydes tethered to an α,β‐unsaturated ketone motif. A tandem O‐Michael addition reaction was completed via acid catalysis.
已经开发了一种不对称的aza-Diels-Alder和O - Michael加成序列,从N -Ts-1-aza-1,3开始,构建了具有良好收率和优异立体选择性的手性氢吡喃并[2,3- b ]吡啶衍生物。-α,β-不饱和酮基拴系的丁二烯和脂族醛。通过酸催化完成了O- Michael串联反应。
Kovalev,B.G. et al., Journal of Organic Chemistry USSR (English Translation), 1969, vol. 5, p. 1722 - 1726