镍( II )催化的γ-烷基单取代的α,β-不饱和丁内酰胺与α,β-不饱和羰基化合物的不对称直接乙烯基Michael加成,以良好的收率和令人满意的对映选择性得到γ,γ-二烷基取代的丁内酰胺。基于该反应还开发了串联催化不对称插烯迈克尔加成/分子内迈克尔加成,这使得能够构建具有三个连续立体碳中心的对映体富集的八氢吲哚。
Enantioselective Addition of Alkynyl Ketones to Nitroolefins Assisted by Brønsted Base/H‐Bonding Catalysis
作者:Teresa E. Campano、Igor Iriarte、Olatz Olaizola、Julen Etxabe、Antonia Mielgo、Iñaki Ganboa、José M. Odriozola、Jesús M. García、Mikel Oiarbide、Claudio Palomo
DOI:10.1002/chem.201805542
日期:2019.3.21
sets of enolizable alkynyl ketones (including methyl ynones with α‐aryl, α‐alkenyl, and α‐alkoxy groups) were able to react smoothly with nitroolefins with the assistance of bifunctional Brønsted base/H‐bond catalysts to provide adducts with two consecutive tertiary stereocenters in a highly diastereo‐ and enantioselective fashion. Further transformation of the obtained adducts into optically active acyclic
catalysts reported before were unsuccessful in this enantioselective radical C−N bond formation. The surprising preference for rhodium over iridium is attributed to much faster ligand‐exchange kinetics of the rhodium complexes involved in the catalytic cycle, which is crucial to keep pace with the highly reactive and thus short‐lived nitrogen‐centered radical intermediate.
Enantioselective Conjugate Addition of 2-Acylimidazoles with Nitroalkenes Promoted by Chiral-at-Metal Rhodium(III) Complexes
作者:Ganesh Kumar Thota、Gui-Jun Sun、Tao Deng、Yi Li、Qiang Kang
DOI:10.1002/adsc.201701377
日期:2018.3.20
An enantioselective conjugate addition of 2‐acylimidazoles with nitroalkenes catalyzed by chiral‐at‐metal rhodium(III) complex under mild reaction conditions was developed, affording versatile γ‐nitro ketone skeletons in good yields with excellent enantioselectivities (up to >99% ee).
Gold‐Catalyzed [3+2]‐Annulations of α‐Aryl Diazoketones with the Tetrasubstituted Alkenes of Cyclopentadienes: High Stereoselectivity and Enantioselectivity
作者:Ching‐Nung Chen、Wei‐Min Cheng、Jian‐Kai Wang、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/anie.202012611
日期:2021.2.23
This work reports gold‐catalyzed [3+2]‐annulations of α‐diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3‐dihydrofurans with high regio‐ and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]‐annulations with α‐diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral
Iron-Catalyzed Synthesis of Tetrahydronaphthalenes via 3,4-Dihydro-2<i>H</i>-pyran Intermediates
作者:Rebecca B. Watson、Corinna S. Schindler
DOI:10.1021/acs.orglett.7b03367
日期:2018.1.5
The development of an iron(III)-catalyzedsynthetic strategy toward functionalized tetrahydronaphthalenes is described. This approach is characterized by its operational simplicity and is distinct from currently available procedures that rely on [4 + 2]-cycloadditions. Our strategy takes advantage of the divergent reactivity observed for simple aryl ketone precursors to gain exclusive access to tetrahydronaphthalene