- Chiral Benzhydrol-2,3,4,5,6-d5
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(-)-Benzhydrol-2,3,4,5,6-d5, C6H5C*HOHC6D5, 20D -0.85 deg (c 16, CHCl3), has been prepared from resolved, enantiomerically pure (+)-4'-nitrobenzhydrol-2,3,4,5,6-d5, by reduction, diazotization, and replacement of the diazonium group with hydrogen using hypophoaphorous acid.The enantiomeric purity of this material was found to be 86percent by use of a chiral NMR shift reagent. (-)-Benzhydrol-2,3,4,5,6-d5 was converted with thionyl chloride-lutidine into (-)-benzhydryl-2,3,4,5,6-d5 chloride .It was previously reported that (+)-1 gave (-)-8 using thionyl chloride-lutidine.Circular dichroism spectra of (-)-1 and (-)-8, which are chiral by virtue of deuterium substitution, are complex and rich in detail in the 240-300-nm region.
- Makino, Taketoshi,Orfanopoulos, Michael,You, Tian-Pa,Wu, Biqi,Mosher, Carol W.,Mosher, Harry S.
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- Base-Promoted Aerobic Oxidation/Homolytic Aromatic Substitution Cascade toward the Synthesis of Phenanthridines
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The current protocol represents a transition metal-free synthesis of polysubstituted phenanthridines from abundant starting materials like benzhydrol and 2-iodoaniline derivatives. The reaction involves sequential oxidation of alcohol and direct condensation reaction with the amine resulting in a C?N bond formation followed by a radical C?C coupling in a cascade sequence. The used base potassium tert-butoxide plays a dual role in dehydrogenation and homolytic aromatic substitution reaction. Using this methodology, twenty substituted phenanthridine derivatives were synthesized with up to 85% isolated yield. (Figure presented.).
- Maiti, Debabrata,Halder, Atreyee,De Sarkar, Suman
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supporting information
p. 4941 - 4948
(2019/11/03)
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- Co(III)-Catalyzed Synthesis of Quinazolines via C-H Activation of N-Sulfinylimines and Benzimidates
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C-H activation of arenes has been established as an important strategy for heterocycle synthesis via annulations between arenes and unsaturated coupling partners. However, nitriles failed to act as such a coupling partner. Dioxazolones have been employed as a synthon of nitriles, and subsequent coupling with arenes such as N-sulfinylimines and benzimidates bearing a functionalizable directing group provided facile access to two classes of quinazolines under Co(III)-catalysis.
- Wang, Fen,Wang, He,Wang, Qiang,Yu, Songjie,Li, Xingwei
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supporting information
p. 1306 - 1309
(2016/04/01)
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- Synthesis of ortho-acylphenols through the palladium-catalyzed ketone-directed hydroxylation of arenes
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ortho-Acylphenols are an important structural motif found in a diversity of bioactive molecules ranging from natural products to drugs (Figure 1). Moreover, they also serve as versatile building blocks for the synthesis of various pharmaceuticals, such as warfarin, as well as agrichemicals, flavors, and fragrances. Classic approaches to the synthesis of o-acylphenols generally involve a two-step process: acylation of phenols followed by Fries rearrangement of the resulting phenyl esters (Scheme 1a). On the other hand, direct C-acylation of phenols has also been known under more forcing conditions. Although effective, these approaches are often complicated by the formation of undesired p-substituted products when bulky acyl groups need to be introduced, as well as the limited variety of ketones that can be generated.
- Mo, Fanyang,Trzepkowski, Louis J.,Dong, Guangbin
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supporting information
p. 13075 - 13079
(2013/02/25)
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- Reactions and mechanistic studies of rhenium-catalyzed insertion of α,β-unsaturated carbonyl compounds into a C-H bond
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A rhenium complex, [ReBr(CO)3(thf)]2, catalyzes the insertion of α, β-unsaturated carbonyl compounds into a C-H bond of aromatic compounds having nitrogen-containing directing groups. In this reaction, Re2(CO)10 can also be used as a catalyst. When imines are employed as the aromatic substrates, sequential cyclization proceeds and indene derivatives are obtained in good to excellent yields. This reactivity is in contrast to those of ruthenium and rhodium complexes, which are usually used as catalysts in the insertion reactions of unsaturated molecules into a C-H bond. Investigations on the reaction mechanism indicate that the rhenium catalyst promotes C-H bond activation of aromatic compounds, the insertion of α, β-unsaturated carbonyl compounds into a Re-C bond, and intramolecular nucleophilic cyclization followed by reductive elimination and the elimination of an amine.
- Kuninobu, Yoichiro,Nishina, Yuta,Okaguchi, Kayo,Shouho, Makoto,Takai, Kazuhiko
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experimental part
p. 1393 - 1401
(2009/05/06)
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- Inter- and Intra-annular Proton Exchange in Gaseous Benzylbenzenium Ions (Protonated Diphenylmethane)
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Two distinct proton exchange reactions occur in metastable gaseous benzylbenzenium ions, generated by isobutane chemical ionization of diphenylmethane and four deuterium-labelled analogues.Whereas the proton ring-walk at the benzenium moiety is fast givin
- Kuck, Dietmar,Baether, Wolfgang
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p. 451 - 458
(2007/10/02)
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- REACTIONS OF BENZENE VAPOR-CALCIUM ATOM WITH ORGANIC HALIDES AND CARBONYL COMPOUNDS
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Reactions of benzene vapor-calcium atom with organic halides and carbonyl compounds were examined.Benzene vapor-calcium atom reacted with organic halides (RX) to give phenyl-substituted products (PhR) and reduced products (RH).The reactions of benzene vapor-calcium atom with ketones (RR'CO) or benzaldehyde gave two kinds of alcohol PhRR'COH and RR'CHOH, or Ph2CHOH and PhCH2OH, respectively
- Mochida, Kunio,Takeuchi, Hidenori,Hiraga, Yoo,Ogawa, Hiroyasu
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p. 1989 - 1992
(2007/10/02)
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