65786-11-0Relevant articles and documents
First catalytic and green synthesis of aryl-(Z)-vinyl chlorides and its plausible addition-elimination mechanism
Su, Weike,Jin, Can
, p. 993 - 996 (2007/10/03)
(Chemical Equation Presented) Via a catalytic cycle in the presence of scandium triflate (2 mol %)/DMF (1 mol %)/benzoyl chloride (5 mol %), aromatic ketones were treated with bis(trichloromethyl) carbonate (BTC) to afford aryl-(Z)-vinyl chlorides. All metal triflates tested in the reaction showed highly catalytic activity. A plausible addition-elimination mechanism was proposed. The present work describes the first catalytic and green route to the synthesis of aryl-(Z)-vinyl chlorides.
Method for chlorinating ketones
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Example 2, (2008/06/13)
In a process for chlorinating ketones which, apart from the carbonyl group, are inert in respect of triarylphosphine dichlorides, except for cyclopropyl methyl ketone, in which the ketones are reacted with a chlorinating agent in the presence of triarylphosphine oxides, the amount of triarylphosphine oxide is from 0.1 to 10 mol %, based on the amount of ketone. The ketones preferably have a least one CH-acid proton in the α position to the carbonyl group.
Surface-Mediated Reactions. 4. Hydrohalogenation of Alkynes
Kropp, Paul J.,Crawford, Scott D.
, p. 3102 - 3112 (2007/10/02)
The use of appropriately prepared silica gel and alumina has been found to mediate the addition of hydrogen halides to alkynes.The technique has been rendered even more convenient by the use of various organic and inorganic acid halides that react in the presence of silica gel or alumina to generate hydrogen halides in situ.Treatment in this fashion of 1-propynylbenzene (1), which underwent no reaction in CH2Cl2 solution saturated with HCl, readily afforded the syn addition product, alkenyl chloride (E)-4a.On extended treatment (E)-4a underwent subsequent iaomerization to the thermodynamically more stable Z isomer.Thus either isomer of 4a could be obtained in good yield depending on the reaction conditions.In a similar way bromides (E)- and (Z)-4b were obtained without competing formation of the radical products (E)- and (Z)-5, which occurred in solution.In contrast with solution-phase hydroiodination of alkyne 1, which slowly afforded iodide (E)-4c, surface-mediated addition readily afforded (E)-4c, followed by isomerization to the Z isomer.E ->/- Z equilibration of the alkenyl halides 4 was shown to involve, at last in part, addition-elimination via the gem-dihalides 13.Analogous behavior was exhibited by the phenylalkynes 2 and 3 on surface-mediated hydrohalogenation.Surface-mediated addition of HBr and HI to the internal alkylalkyne 14 afforded principally the anti addition products (Z)-15b,c.Treatment of the terminal alkynes 17 and 22 with (COBr)2 over alumina gave the dibromides 20 and 24/25, respectively, whereas use of acetyl bromide as the HBr precursor afforded the alkenyl bromides 18b and 23.
ADDITION OF IODINE-BASED ELECTROPHILIC REAGENTS TO SOME VINYLSILANES
Grayson, Elizabeth J.,Witham, Gordon H.
, p. 4087 - 4094 (2007/10/02)
The addition of some iodine-based electrophilic reagents to the cyclic vinylsilanes (1) and (4, R=But, R1=H) and (4, R=H, R1=OMe) occurs with high regio- and stereo-specificity to give (2, X=OMe, N3 and NCS) and (5, R=But, R1=H, X=OMe and N3) and (5, R=H, R1=OMe, X=OMe).Similar additions to 2-trimethylsilylhept-1-ene (6) are less efficient and occur with lower regioselectivity.Some of the adducts (2) and (5) have been transformed into functionalised organosilanes.Compounds (10, X=OMe, N3, and NCS) and (12)-(15) are thereby obtained.
