A convenient preparation of allenyl aryl ketones was achieved by the Weinreb-modified Grignard reaction of N-methoxy-N-methylamides with propargylmagnesium bromide. On treatment with BF3·OEt2, the allenyl aryl ketones were converted to methylenebenzocyclopetenones via a new 5-endo-mode cyclization.

Dedicated to the memory of professor In-Kyu Kim) Esterification of aliphatic or aromatic carboxylic acids with alcohols using 2-(4-nitrobenzenesulfonyl)-4,5dichloropyridazin-3(2H)-one (3) in the presence of base in organic solvents gave the corresponding esters in excellent yields

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