135457-36-2Relevant academic research and scientific papers
Chiral Allenes via Alkynylogous Mukaiyama Aldol Reaction
Tap, Aurélien,Blond, Aurélie,Wakchaure, Vijay N.,List, Benjamin
, p. 8962 - 8965 (2016)
Herein we describe the development of a catalytic enantioselective alkynylogous Mukaiyama aldol reaction. The reaction is catalyzed by a newly designed chiral disulfonimide and delivers chiral allenoates in high yields and with excellent regio-, diastereo
A general method for the synthesis of 2,2-[60]fullerenoalkanals: The reaction of [60]fullerene with 2-bromoenol silyl ethers
Ito, Hiroshi,Kishi, Yusuke,Nishikawa, Yohei,Tada, Tomonori,Ishida, Yasuhiro,Saigo, Kazuhiko
scheme or table, p. 1811 - 1814 (2010/10/19)
Five kinds of 2,2-[60]fullerenoalkanals were synthesized by the fluoride ion-mediated reaction of [60]fullerene with 2-bromoenol silyl ethers, which were easily prepared by 2-bromination of the corresponding enol silyl ethers. The reactivity differed significantly depending on the stability of the 2-bromoenol silyl ethers. High yield and selectivity were achieved for the reaction of 2-bromoenol trimethylsilyl ethers under mild conditions (KF/18-crown-6-ether). The reaction of stable 2-bromoenol tert-butyldimethylsilyl ethers, on the other hand, required the use of more reactive tetrabutylammonium fluoride as a fluoride ion source. Georg Thieme Verlag Stuttgart.
A practical reversed-polarity alternative to organocuprate conjugate addition chemistry. Halocarbon coupling reactions of enal- and enone-derived allylnickel reagents
Johnson, John R.,Tully, Paul S.,Mackenzie, Peter B.,Sabat, Michal
, p. 6172 - 6177 (2007/10/02)
A direct method for the conversion of conjugated enals and enones into [1-[(trialkylsilyl)oxy]allyl]nickel(II) chloride complexes is described. Reaction of R1CH=CR2CHO (R1 = H, Me, Ph; R2 = H and R2 = H; R2 = Me) with Ni(COD)2 (COD = 1,5-cyclooctadiene) and ClSiMe2R3 (R3 = Me or t-Bu) affords bis[[1,2,3-η 3-1-[(trialkylsilyl)oxy]-2-propenyl](μ-chloro)nickel(II)] complexes 1a-f as burgundy-red crystalline solids in high to excellent yields (86-98%). The X-ray crystal structure of 1c confirms the η3-bonding mode for the allyl ligand and provides evidence of significant overlap of oxygen lone pair electron density with the allyl π-system. Reaction of 3-buten-2-one with Ni(COD)2 and Me3SiCl similarly affords bis[[1,2,3-η 3-1-methyl-1-[(trimethylsilyl)oxy]-2-propenyl](μ-chloro)nickel(II) ] (1g) in 72% yield, while the corresponding 2-cyclopentenone reaction fails, giving rise to a nickel metal mirror. The latter reaction does, however, succeed when conducted in the presence of pyridine, giving bis(pyridine)(chloro)[1,2,3-η 3-1-[(tert-butyldimethylsilyl)oxy]-2-cyclopentenyl]nickel(II) complex (1h) in 95% yield. Irradiation of 1e (R1 = R2 = H; R3 = t-Bu) in the presence of 2-iodopropane affords tert-butyldimethylsilyl (E)-enol ether 2a in 78% yield (E:Z = 10:1). Similar results are observed with [1-[(trialkylsilyl)oxy]allyl]nickel(II) chloride complexes generated in situ from propenal, 2-methylpropenal, 2-butenal, 2-methyl-2-butenal, hexenal, and 3-buten-2-one, in coupling reactions with 1-iodobutane, 2-iodopropane, 1-bromoethene, 2-bromopropene, bromobenzene, o-bromobenzaldehyde, and isobutyryl chloride, affording the corresponding silyl (E)-enol ethers in 60-78% isolated, purified yield, based on Ni(1,5-COD)2. High C(3) regioselectivities (>20:1) are observed for all of the C(3)-unsubstituted enals, while lower regioselectivities, in the range of 4-6:1 before purification, are observed for the C(3)-substituted enals; regioisomerically pure materials are obtained upon chromatography. Moderate to high E:Z stereoselectivities (E:Z = 4-15:1 before purification; E:Z = 20-50:1 after chromatography) are observed in all cases, save the reaction of isobutyryl chloride with 1e and the reaction of the 3-buten-2-one-derived allylnickel complex with 2-bromopropene, both of which give 1:1 E:Z ratios. In a more convenient, economical, and general variant, Ni(COD)2 is generated in situ via the sodium metal reduction of NiCl2(pyridine)4 (in turn prepared from NiCl2(H2O)6) in the presence of cyclooctadiene and reacted with the enal or enone in the presence of ClSiMe2R3 to afford the [1-[(trialkylsilyl)oxy]allyl](chloro)(pyridine)nickel(II) complex, which is treated with the halocarbon and irradiated to afford the usual silyl enol ether products. Yields of 63-84%, based on enal or enone, were observed in reactions with propenal, (E)-2-hexenal, 2-cyclopentenone, and 2-cyclohexenone in reactions with bromoethene, bromobenzene, and 1-iodobutane using this procedure.
