Conjugated polyenic tellurides as novel building blocks: A facile and novel stereoselective preparation of conjugated polyenic ketones
摘要:
Upon treatment with butyllithium followed by adding zinc halide, conjugated polyenic tellurides smoothly undergo a Pd(0)-catalyzed cross coupling reaction with acyl chlorides to form the pure thermodynamically more stable conjugated polyenic ketones in good yield, regardless of the configuration of the telluride used. (C) 1998 Elsevier Science Ltd. All rights reserved.
3‐substituted oxindoles to dienylketones has been developed. This procedure tolerates a relatively wide range of 3‐substituted oxindoles under mild conditions, facilitating the preparation of various chiral oxindoles with quaternary stereocenters. In addition, the reliable catalyst was found to be effective in the asymmetric 1,6‐addition of both δ‐unsubstituted and δ‐methyl‐substituted dienylketones, achieving
1,6-Addition Reaction of 5<i>H</i>-Oxazol-4-ones to Conjugated Dienones Catalyzed by Chiral Guanidines
作者:Akane Morita、Tomonori Misaki、Takashi Sugimura
DOI:10.1246/cl.140713
日期:2014.12.5
A chiral guanidine-catalyzed 1,6-addition reaction of 5H-oxazol-4-ones to α,β,γ,δ-diunsaturated ketones is described in this study. The addition reaction proceeded regiospecifically to yield a 1,6-addition product with high enantioselectivity. Obtained adducts of the 1,6-addition could be converted into the corresponding chiral 7-oxo-α-hydroxy acid derivatives or chiral α-homoallylic-hydroxy acid derivatives via 2nd generation Grubbs catalyst-mediated olefin metatheses.
Cu-catalyzed carboboration of acetylene with Michael acceptors
作者:Tairan Cheng、Boxiang Liu、Rui Wu、Shifa Zhu
DOI:10.1039/d2sc02306g
日期:——
A copper-catalyzed three-component carboboration of acetylene with B2Pin2 and Michael acceptors is reported. In this reaction, a cheap and abundant C2 chemical feedstock, acetylene, was used as a starting material to afford cis-alkenyl boronates bearing a homoallylic carbonyl group. The reaction was robust and could be reliably performed on the molar scale. Furthermore, the resulting cis-alkenyl boronates
报道了铜催化乙炔与 B 2 Pin 2和 Michael 受体的三组分碳硼化反应。在该反应中,使用廉价且丰富的C2化学原料乙炔作为起始原料,得到带有同烯丙基羰基的顺式烯基硼酸酯。该反应很稳健,并且可以在摩尔规模上可靠地进行。此外,所得顺式烯基硼酸酯可以轻松转化为多种功能化分子。
作者:Hongyi Li、Chang Yin、Sien Liu、Hua Tu、Ping Lin、Jing Chen、Weiping Su
DOI:10.1039/d2sc05370e
日期:——
The dehydrogenation-triggered multiple C(sp3)–H functionalizations at remote positions γ, δ or ε, ζ to carbonyl groups of aliphatic ketones with aryl/alkenyl carboxylic acids as coupling partners have been achieved using a bimetallic Cu–Pd catalyst system. This reaction allows access to alkenylated isocoumarins and their derivatives in generally good yields with high functional group tolerance. The
A Pd0complex can mediate dehydrogenative formation of 2,4-diene systems from γ,δ-unsaturated carbonyls in the presence of 2,6-DMBQ (2,6-dimethyl-1,4-benzoquinone), which undergo vinylogous addition to imines via auto-tandem Pd0-π-Lewis base catalysis. Both chemically inverse δ-regioselective aza-Morita–Baylis–Hillman adducts and α-regioselective normal ones are obtained switchably and stereoselectively