84363-88-2Relevant academic research and scientific papers
Photocatalytic Umpolung Synthesis of Nucleophilic π-Allylcobalt Complexes for Allylation of Aldehydes
Shi, Caizhe,Li, Fusheng,Chen, Yuqing,Lin, Shuangjie,Hao, Erjun,Guo, Zhuowen,Wosqa, Urwa Tul,Zhang, Dandan,Shi, Lei
, p. 2992 - 2998 (2021/03/09)
The concept of "umpolung"reactivity of π-allylmetal complexes has been developed as a powerful method for the allylation of aldehydes. This paper describes the photocatalytic umpolung strategy for the synthesis of nucleophilic allylcobalt complexes through a single-electron-transfer (SET) process. This strategy enables the metallaphotoredox allylation of carbonyls with allyl acetate using organic N,N-diisopropylethylamine as the terminal reductant bypassing the use of a stoichiometric amount of metals. Ultraviolet-visible spectroscopy was used to monitor the redox changes of cobalt in the reaction.
Nickel-Catalysed Allylboration of Aldehydes
Dennis, Francesca M.,Partridge, Benjamin M.,Robertson, Craig C.
, p. 1903 - 1914 (2020/07/04)
A nickel catalyst for the allylboration of aldehydes is reported, facilitating the preparation of homoallylic alcohols in high diastereoselectivity. The observed diastereoselectivities and NMR experiments suggest that allylation occurs through a well-defined six-membered transition state, with nickel acting as a Lewis acid.
Catalytic Nucleophilic Allylation Driven by the Water-Gas Shift Reaction
Denmark, Scott E.,Matesich, Zachery D.,Nguyen, Son T.,Milicevic Sephton, Selena
, p. 23 - 48 (2018/02/19)
The ruthenium-catalyzed allylation of aldehydes with allylic pro-nucleophiles has been demonstrated to be an efficient means to form carbon-carbon bonds under mild conditions. The evolution of this reaction from the initial serendipitous discovery to its general synthetic scope is detailed, highlighting the roles of water, CO, and amine in the generation of a more complete catalytic cycle. The use of unsymmetrical allylic pro-nucleophiles was shown to give preferential product formation through the modulation of reaction conditions. Both (E)-cinnamyl acetate and vinyl oxirane were efficiently used to form the anti-branched products (up to >20:1 anti/syn) and E-linear products (up to >20:1 E/Z) in high selectivity with aromatic, α,β-unsaturated, and aliphatic aldehydes, respectively. Attempts to render the reaction enantioselective are highlighted and include enantioenrichment of up to 75:25 for benzaldehyde.
Facile synthesis of (Z)-anti-homoallylic alcohols from 3-(pinacolatoboryl)allyl alcohols, aldehydes, and triorganoboranes via a palladium-catalyzed three-component reaction
Horino, Yoshikazu,Aimono, Ataru,Minoshima, Naoki,Abe, Hitoshi
supporting information, p. 3561 - 3564 (2016/07/15)
A palladium-catalyzed three-component reaction of 3-(pinacolatoboryl)allyl alcohols, aldehydes, and triorganoboranes was developed. The present protocol provides facile access to synthetically useful (Z)-anti-homoallylic alcohols with high diastereoselect
Pd-catalyzed three-component reaction of 3-(Pinacolatoboryl)ally acetates, aldehydes, and organoboranes: A new entry to stereoselective synthesis of (Z)- anti -homoallylic alcohols
Horino, Yoshikazu,Aimono, Ataru,Abe, Hitoshi
supporting information, p. 2824 - 2827 (2015/06/16)
The Pd-catalyzed three-component reaction of 3-(pinacolatoboryl)allyl acetates, aldehydes, and organoboranes is described. The reaction is initiated by the formation of an allylic gem-palladium/boryl intermediate, which then undergoes allylation of aldehydes by allylboronates followed by a coupling reaction of in situ generated (Z)-vinylpalladium acetates with organoboranes to provide the (Z)-anti-homoallylic alcohols with high levels of diastereoselectivity and alkene stereocontrol.
Diastereoselective carbonyl allylation with simple olefins enabled by palladium complex-catalyzed C-H oxidative borylation
Tao, Zhong-Lin,Li, Xing-Han,Han, Zhi-Yong,Gong, Liu-Zhu
supporting information, p. 4054 - 4057 (2015/04/14)
A highly diastereoselective Pd-catalyzed carbonyl allylation of aldehydes and isatins directly using simple acyclic olefins as allylating reagents is described. This transformation is actually a sequential process consisting of a Pd-catalyzed oxidative allylic C-H borylation and an allylboration of carbonyls accelerated by phosphoric acid, wherein a wide scope of olefins could be tolerated. The oxidant is revealed to play a key role in the successful realization of the allylic C-H activation-based allylation.
Stereocontrolled palladium-catalysed umpolung allylation of aldehydes with allyl acetates
Vogt, Monika,Ceylan, Sascha,Kirschning, Andreas
experimental part, p. 6450 - 6456 (2010/10/19)
In the present work the stereocontrolled palladium-catalysed umpolung allylation of aldehydes is described. Allyl acetates are in situ transformed into the corresponding allyl boronates, which directly react with aldehydes. The question of stereocontrol is raised by employing (a) chiral boronating agents (reagent control) and by (b) utilising chiral aldehydes (substrate control). These studies reveal that the approach based on substrate control is superior to the former one with respect to yields and stereoselectivity. Remarkably, this umpolung protocol often yields the 4,5-syn products in high selectivity, which is unprecedented for direct crotylations.
Regio- and stereoselective synthesis of homoallylic alcohols based on the use of (3-chloroprop-1-en-1-yl)boronates
Lombardo, Marco,Morganti, Stefano,Tozzi, Massimo,Trombini, Claudio
, p. 2823 - 2830 (2007/10/03)
A set of (3-chloroprop-1-en-1-yl)boronates 10 were synthesised, starting from (3-chloroprop-1-en-1-yl)bis(isopinocampheyl)borane. Quaternisation of 10 by Grignard methodology afforded "ate" species 14, which underwent spontaneous anionotropic rearrangement to give the substituted allylboronates 15. By a suitable choice of the diol component in 10 and of the reaction temperature, α- or γ-substituted allylboronates 15 or 16 could be selectively produced, offering routes to homoallylic alcohols 9 or anti-8, respectively, after treatment with an aldehyde. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Palladium-catalyzed carbonyl allylation by allylic alcohols with SnCl2
Takahara, Jun P.,Masuyama, Yoshiro,Kurusu, Yasuhiko
, p. 2577 - 2586 (2007/10/02)
Allylic alcohols can be applied to carbonyl allylation via the formation of π-allylpalladium complexes, using palladium as catalyst and SnCl2 as a reducing agent. This reaction has chemoselectivity: The reactivity order of allylating agents is allylic carbonate > allylic alcohol > allylic acetate, and that of carbonyl compounds is aldehyde > ketone. High regioselcction was observed in polar solvents such as DMF, DMI, and DMSO; carbonyl compounds apparently attacked the more substituted allylic position of π-allylpalladium complexes to afford only one regioisomer. Diastereocontrol in the carbonyl allylation of aromatic aldehydes by (E)-2-butenol was achieved by the choice of polar solvents; use of DMSO at 25 °C led to syn selection, while anti selection was found at -10 °C in THF. The addition of H2O in any solvent accelerated the carbonyl allylation and enhanced both regioselectivity and the diastereoselectivity. Anti selection in DMF, DMI, and THF-H2O can be explained by the chair form of the six-membered cyclic transition state, while syn selection in DMSO allows us to propose an acyclic antiperiplanar transition state. An NMR spectroscope investigation demonstrated that the actual allylating agent in dry medium was allyltrichlorotin: 1H, 13C, and 119Sn NMR spectra of the reaction of allyl alcohol with PdCl2(PhCN)2-SnCl2 in DMF-d7. corresponded to those of the reaction of allyl chloride with PdCl2(PhCN)2-SnCl2 in DMF-d7.
