354530-00-0Relevant academic research and scientific papers
Direct α-Acylation of Alkenes via N-Heterocyclic Carbene, Sulfinate, and Photoredox Cooperative Triple Catalysis
Liu, Kun,Studer, Armido
supporting information, p. 4903 - 4909 (2021/05/04)
N-Heterocyclic carbene (NHC) catalysis has emerged as a versatile tool in modern synthetic chemistry. Further increasing the complexity, several processes have been introduced that proceed via dual catalysis, where the NHC organocatalyst operates in concert with a second catalytic moiety, significantly enlarging the reaction scope. In biological transformations, multiple catalysis is generally used to access complex natural products. Guided by that strategy, triple catalysis has been studied recently, where three different catalytic modes are merged in a single process. In this Communication, direct α-C-H acylation of various alkenes with aroyl fluorides using NHC, sulfinate, and photoredox cooperative triple catalysis is reported. The method allows the preparation of α-substituted vinyl ketones in moderate to high yields with excellent functional group tolerance. Mechanistic studies reveal that these cascades proceed through a sequential radical addition/coupling/elimination process. In contrast to known triple catalysis processes that operate via two sets of interwoven catalysis cycles, in the introduced process, all three cycles are interwoven.
Asymmetric Catalytic Epoxidation of Terminal Enones for the Synthesis of Triazole Antifungal Agents
Feng, Xiaoming,He, Qianwen,Liu, Xiaohua,Zhang, Dong,Zhang, Fengcai
supporting information, p. 6961 - 6966 (2021/09/11)
An enantioselective epoxidation of α-substituted vinyl ketones was realized to construct the key epoxide intermediates for the synthesis of various triazole antifungal agents. The reaction proceeded efficiently in high yields with good enantioselectivities by employing a chiral N,N′-dioxide/ScIII complex as the chiral catalyst and 35% aq. H2O2 as the oxidant. It enabled the facile transformation for optically active isavuconazole, efinaconazole, and other potential antifungal agents.
Palladium-Catalyzed Carbonylative Synthesis of α-Branched Enones from Aryl Iodides and Arylallenes
Geng, Hui-Qing,Hou, Chen-Yang,Wang, Le-Cheng,Wu, Xiao-Feng
supporting information, p. 1160 - 1163 (2020/02/26)
In this communication, an interesting carbonylation protocol for the preparation of α-branched enones has been established. Starting from readily available aryl iodides and allenes, with formic acid as the CO source and reductant, moderate to good yields of the desired enones were isolated. Although it is a carbonylation methodology, the use of a CO source can avoid the manipulation of CO gas directly. Notably, this procedure also presents the first example on carbonylative synthesis of α-branched enones.
Iron-Catalyzed Tandem Three-Component Alkylation: Access to α-Methylated Substituted Ketones
Bettoni, Léo,Seck, Charlotte,Mbaye, Mbaye DIagne,Gaillard, Sylvain,Renaud, Jean-Luc
supporting information, p. 3057 - 3061 (2019/05/10)
The borrowing hydrogen strategy has been applied in the synthesis of α-branched methylated ketones via a tandem three-component reaction catalyzed by a diaminocyclopentadienone iron tricarbonyl complex. Various alkyl and aromatic methyl ketones underwent dialkylation with various primary alcohols and methanol as alkylating agents in mild reaction conditions and good yields. Deuterium labeling experiments suggested that the benzylic alcohol was the hydrogen source in this tandem process.
Preparation of α-methylene ketones by direct methylene transfer
Rodrigues, J. Augusto R.,Siqueira-Filho, Ezequias P.,De Mancilha, Moacir,Moran, Paulo J. S.
, p. 331 - 340 (2007/10/03)
Four methods for the preparation of α-methylene ketones by direct methylene transfer are presented. The procedures were optimized in order to obtain high yields.
Efficient and selective hydroacylation of 1-alkynes with aldehydes by a chelation-assisted catalytic system
Jun, Chul-Ho,Lee, Hyuk,Hong, Jun-Bae,Kwon, Bong-Il
, p. 2146 - 2147 (2007/10/03)
Terminal alkynes successfully undergo chelation-assisted hydroacylation with aldehydes to give branched or linear alkyl α,β-unsaturated ketones (see scheme).
Baker's yeast reduction of α-methyleneketones
Siqueira Filho, Ezequias P.,Rodrigues, J.Augusto R.,Moran, Paulo J.S.
, p. 847 - 852 (2007/10/03)
The bioreduction of α-methyleneketones, R1C(=O)C(=CH2)R2 (R1 = Me, Et, Pr, iso-Bu, Ph, CH2CH2Ph; R2 = Cl, Me, Et, n-Pr, iso-Pr, n-Bu, n-C6H13, Ph, CH2Ph), was mediated by baker's yeast (Saccharomyces cerevisiae) to obtain the corresponding α-methylketones. The R1 and R2 groups had a significant influence on the rate and enantioselectivity of the reductions. The rate of C=C bond reduction was higher than that of C=O bond reduction. Only α-methyleneketones having R1 = Me yielded α-methylketones in high enantioselectivity with e.e.s of 88-99%.
