Contrasting steric effects of the ketones and aldehydes in the reactions of the diisopinocampheyl enolborinates of methyl ketones with aldehydes
作者:P.Veeraraghavan Ramachandran、Wei-chu Xu、Herbert C. Brown
DOI:10.1016/0040-4039(96)00969-0
日期:1996.7
representative series of aldehydes, both of differing steric requirements provides aldols whose enantiomeric purities depend on the steric requirements of both the ketones and the aldehydes. This study has shown that increasing the steric requirements of the R group in the ketones has a pernicious effect on the ee, while increasing the steric requirements of the R group in the aldehydes exerts a beneficial
Catalytic asymmetric synthesis of β-hydroxy ketones by palladium-catalyzed asymmetric 1,4-disilylation of α,β-unsaturated ketones
作者:Yonetatsu Matsumoto、Tamio Hayashi、Yoshihiko Ito
DOI:10.1016/s0040-4020(01)80758-4
日期:1994.1
1,4-Disilylation of β,β-unsaturatedketones with 1,1-dichloro-l-phenyl-2,2,2-trimethyldisilane proceeded in the presence of phosphine-palladium catalysts in benzene. High enantio-selectivity (up to 92%) was observed in the disilylation with dichloro[(R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]palladium(II) as a catalyst (0.5 mol %). The disilylation products, 1-(trimethyisilyloxy)-3-(dichlorophenylsilyl)propenes
Copper pins on the boron: The enantioselective 1,4‐addition of diboron to α,β‐unsaturatedcompounds proceeds smoothly in the presence of catalytic amounts of Cu(OH)2 and chiral 2,2′‐bipyridine ligand in water. A wide substrate scope of α,β‐unsaturatedcarbonylcompounds, including acyclic, cyclic, and β,β‐disubstituted enones, α,β‐unsaturated esters, amides, and a nitrile, has been shown.
Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways To Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
作者:Victor Laserna、Michael J. Porter、Tom D. Sheppard
DOI:10.1021/acs.joc.9b00988
日期:2019.9.20
Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines
Copper-Catalyzed Enantioselective β-Boration of Acyclic Enones
作者:Hak-Suk Sim、Xinhui Feng、Jaesook Yun
DOI:10.1002/chem.200802150
日期:2009.2.9
Josi or Mandy? Asymmetric conjugate addition of diboron to acyclicenones catalyzed by copper affords chiral organoboronates that possess a boronate group at the β stereocenter with excellent chemical yields and enantioselectivities (see scheme). This method accommodates the structural variation of acyclicenones and provides access to highly functionalized chiral organoboronates in one step.