Oxonium fluoroborates salts , Trialkyloxonium

Nitro compounds, ar. Nitrobenzene, m-Dinitrobenzene o Nitrophenol N-Nitramines Oxonium fluoroborate Trialkyloxonium salt T rialkyloxonium fluoroborate Pyrylium fluoroborate Carboxylic acid esters HCOOC2HS, p-Nitro-phenyl formate Isopropenyl acetate Ethyl cyanoacetate Chloroformic acid esters Ethyl chloroformate Methyl trichloroacetate Diethyl oxalate Ethyl malonate Orthoformic acid esters, Ethyl orthoformate (RC0)20 (CHsC0)20,... [Pg.277]

Oxonium fluoroborate Trialkyloxonium salt - fluoroborate Pyrylium fluoroborate Carboxylic acid esters HCOOEt, p-Nitro-phenyl formate Isopropenyl acetate Salicylic acid esters Ethyl cyanoacetate Chloroformic acid esters... [Pg.630]

Nitro compounds, ar. Nitrobenzene N-Nitramines Oxonium fluoroborate Trialkyloxonium salt Trialkyloxonium fluoroborate Carboxylic acid esters Isopropenyl acetate Chloroformic acid esters Ethyl chloroformate Methyl trichloroacetate... [Pg.258]

No comparison between trialkyloxonium fluoroborates and dialkyl sulfates has been made, but analysis of available data shows that oxonium salts are more generally applicable reagents for the preparation of lactim ethers. The alkylation of 3-carbethoxypiperid-2-one (7)25 and morpholin-3-one (8)32 with dimethyl sulfate failed, but with triethyloxonium fluoroborate these compounds gave 2-ethoxy-3-carbethoxy-3,4,5,6-tetrahydropyridine (9) and 3-ethoxy-3,4-dehydro-morpholine (10) in excellent yield. The selective character of triethyloxonium fluoroborate is shown in its reaction with 3,3-diethyl-5-methylpiperidine-2,4-dione (11 ).25 Reaction of 11 with the calculated quantity of dimethyl sulfate resulted in alkylation of the carbonyl group in position 4 with formation of 12, but reaction of 11 with triethyloxonium fluoroborate gave the lactim ether (13). [Pg.188]

Trialkyloxonium fluoroborates give better yields of lactim ethers than other alkylating agents because of the selectivity of these reagents in the O-alkylation of lactams. This was borne out by Meerwein at al.,42 who arranged carbonyl compounds according to their capacity to undergo alkylation with oxonium salts as follows lactams > acyclic amides > lactones > carboxylic esters > ketones > aldehydes. [Pg.189]