Stereoselective Coupling of Prochiral Radicals with a Chiral <i>C</i><sub>2</sub>-Symmetric Nitroxide
作者:Rebecca Braslau、Neeta Naik、Hendrik Zipse
DOI:10.1021/ja000520u
日期:2000.9.1
The coupling reaction between a chiral C2-symmetric nitroxide, trans-2,5-dimethyl-2,5-diphenylpyrrolidin-1-oxyl (DPPO; 1), and a series of stabilized secondary prochiral radicals was studied to determine the factors that affect stereoselectivity. Both steric and electronic perturbations on the selectivity by the substituents of the prochiral radical were observed. The effects of temperature, solvent
The reaction of various secondary nitro compounds with 1.1 equivalents of potassium hydride in 1,4-dioxane and then with 0.10 equivalent of chlorotrimethylsilane gave the corresponding ketones in 62-90% yields. By a similar strategy, poly(1,3-diketones) were synthesized directly from nitroalkenes with sodium ethoxide, potassium hydride, and chlorotrimethylsilane in 1,4-dioxane. The use of chlorotrimethylsilane
PROCESS FOR THE PREPARATION OF NITRO COMPOUNDS AND METHOD FOR THE REMOVAL OF NITROGEN DIOXIDE
申请人:Daicel Chemical Industries, Ltd.
公开号:EP1099684A1
公开(公告)日:2001-05-16
In the invented process for producing a nitro compound, an organic substrate and nitrogen dioxide are reacted in the presence of oxygen or are reacted in a molar ratio of nitrogen dioxide to the organic substrate of less than 1 to yield a corresponding nitro compound. The reaction may be performed in the presence of N-hydroxyphthalimide or other imide compounds. Such organic substrates include (a) aliphatic hydrocarbons, (b) alicyclic hydrocarbons, (c) non-aromatic heterocyclic compounds each having a carbon atom on a ring, which carbon atom is bonded to a hydrogen atom, (d) compounds each having a carbon-hydrogen bond at the adjacent position to an aromatic ring, and (e) compounds each having a carbon-hydrogen bond at the adjacent position to a carbonyl group. This process can efficiently nitrate an organic substrate even under relatively mild conditions.
Unanticipated Silyl Transfer in Enantioselective α,β-Unsaturated Acyl Ammonium Catalysis Using Silyl Nitronates
作者:Anastassia Matviitsuk、Mark D. Greenhalgh、James E. Taylor、Xuan B. Nguyen、David B. Cordes、Alexandra M. Z. Slawin、David W. Lupton、Andrew D. Smith
DOI:10.1021/acs.orglett.9b04404
日期:2020.1.3
The use of silyl nitronates is reported for the isothiourea-catalyzed synthesis of γ-nitro-substituted silyl esters containing up to two contiguous stereocenters in good yields with excellent enantioselectivities (up to 93% yield and 99:1 er). The serendipitously discovered formation of silyl ester products in this reaction demonstrates a novel platform for catalyst turnover in α,β-unsaturated acyl