61203-03-0Relevant articles and documents
New synthesis and cyclopropanation of α-phenylselanyl α,β-unsaturated ketones with non-stabilized phosphorus ylides
Redon, Sébastien,Leleu, Stéphane,Pannecoucke, Xavier,Franck, Xavier,Outurquin, Francis
, p. 9293 - 9304 (2008/12/22)
A general method for the preparation of α-phenylselanyl enones is described. Phosphorus ylides react with these α-phenylselanyl enones in a 1,4-addition, leading to cyclopropanes and/or dihydrofurans, depending on the substitution pattern. This unusual reactivity is due to the phenylselanyl moiety, hindering the carbonyl of the enone and making it less prone to 1,2-additions or promoting conjugate addition by electronic effects.
A radical cyclization route to pyrrolidines based on conjugate addition to electron deficient phenylselenenylalkenes
Berlin, Stefan,Engman, Lars
, p. 3701 - 3704 (2007/10/03)
α-Phenylselenenyl-α,β-unsaturated esters, amides, ketones, nitriles and sulfones were prepared by zinc chloride promoted chloroselenation/dehydrochlorination of the corresponding α,β-unsaturated compounds. After Michael addition of allyl or propargylamine and triethylborane initiated reductive radical cyclization in the presence of tris(trimethylsilyl)silane, pyrrolidine and dihydropyrrole derivatives, respectively, were obtained. (C) 2000 Elsevier Science Ltd.
CAPTODATIVE SUBSTITUENT EFFECTS XXI. SYNTHESIS OF SELENENYLATED CAPTODATIVE OLEFINS VIA SELENENYL HALIDE ADDITION TO OLEFINS BEARING ELECTRON-WITHDRAWING SUBSTITUENTS
Piettre, S.,Janousek, Z.,Merenyi, R.,Viehe, H. G.
, p. 2527 - 2544 (2007/10/02)
Addition of methane- and benzeneselenenyl bromide or chloride and benzene sulfenyl chloride to carbon-carbon double bonds substituted by electron-withdrawing groups is achieved in solvents of different polarity.Two regioisomeric adducts 6 and 7 or 8 and 9 are generally formed, which can be interconverted by equilibration in refluxing acetonitrile.It is of mechanistic interest that the regioisomers may also derive from selenenyltrihalide adducts.In comparison to acrylic esters, the propiolic ester reacts more slowly, producing mainly the α-selenenyl adduct.Dehydrohalogenation of adducts provides a general and valuable method for the preparation of olefins carrying methyl or phenylselenyl groups in α-position to electron-withdrawing substituents.
Reactions of α-Diazo Ketones with Selenium-based Reagents. A General Synthesis of α-Chloro-, α-Bromo, α-Phenylseleno-, α-Acetoxy-, and α-Methoxy-αβ-unsaturated Ketones
Buckley, Daniel J.,McKervey, M. Anthony
, p. 2193 - 2200 (2007/10/02)
Benzeneselenenyl derivatives, PhSe-X (X=Cl, Br, OCOCH3, and SCN) react readily with α-diazo ketones, RCOC(N2)R1 (R1=H or alkyl), with loss of nitrogen, furnishing αα-adducts of the type RCOCR1(X)SePh.The α-chloro and α-bromo adducts can be converted into α-methoxy adducts in methanol-sodium hydrogen carbonate.The utility of these adducts in synthesis is illustrated by their conversion (where structural considerations permit) via selenoxide fragmentation into α-heterosubstituted αβ-unsaturated ketones.Treatment of the series RCOCR1(X)SePh (R1=alkyl; X=Cl, Br, OCOCH3, and OCH3) with hydrogen peroxide-pyridine produces α-chloro-, α-bromo-, α-acetoxy-, and α-methoxy-αβ-unsaturated ketones, whereas treatment of series RCOCR1(X)SePh (R1=alkyl; X=Cl and Br) with lithium carbonate in dimethylformamide produces α-phenylseleno-αβ-unsaturated ketones.Several α-substituted cyclopentenones, cyclohexenones, and cycloheptenones have been synthesised in this way and acyclic examples are illustrated by the synthesis of 3-chloro-, 3-bromo-, 3-acetoxy-, 3-methoxy,-and 3-phenylselenobut-3-en-2-one from 3-diazobutan-2-one.
CAPTO-DATIVE SUBSTITUENT EFFECTS XIII. C4-BRIDGED RADICAL DIMERISATION WITH α-PHENYLSELENOACRYLIC ACID DERIVATIVES
Janousek, Z.,Piettre, S.,Gorissen-Hervens, F.,Viehe, H.G.
, p. 197 - 202 (2007/10/02)
Several capto-dative olefins containing the phenylselenenyl group have been obtained via selenenyl halide addition to acrylic derivatives followed by halide elimination.Some of the olefins efficiently trap the radicals formed from azobisisobutyronitrile (
Selenium--Stabilized Anions. Preparation of α,β-Unsaturated Carbonyl Compounds Using Propargyl Selenides. Synthesis of (+/-)-7-Hydroxymyoporone
Reich, Hans J.,Shah, Shrenik K.,Gold Paul M.,Olson Richard E.
, p. 3112 - 3120 (2007/10/02)
The reaction of alkyl halides, carbonyl compounds, and trimethylsilyl chloride with the mono- and dianion (1) prepared by deprotonation of phenyl propargyl selenide with lithium diisopropylamide gives 1- or 3-monosubstituted or 1,3-disubstituted propargyl selenides (3a).Oxidation to selenoxides (3b) results in rearrangement to 2-(phenylseleno)-1,3-disubstituted propenones.The rate of rearrangement of propargyl selenoxides increases dramatically when the phenyl group is replaced by a 2-nitrophenyl group, and an intermediate allenyl selenate ester (7c) can be observed by low-temperature NMR.By appropriate modification of oxidation conditions, modest yields of 2-iodopropenes (e.g., 10) or the selenium-free enones or enals can be obtained.A synthesis of (+/-)-7-hydroxymyoporone (15) and its epimer has been carried out by using the dianion 1 to assemble the carbon skeleton.The preparation of α-lithioallenyl phenyl selenide (26) has been accomplished, and its reaction with electrophiles has been studied.
