The Pechmann reaction of substituted phenols 1a-e with methyl acetoacetate (2) can be activated by boron trifluoride dihydrate (3) to give the corresponding 4-methyl- coumarin derivatives 4a-e in excellent yield (98-99 %).

This paper describes the selective reductions with thioborane derivatives, zinc—modified cyanoborohydride, and the ate complex from diisobutylaluminum hydride and n-butyllithium. Reaction of carboxylic acids with 1,3,2-dithiaborinane in the presence of stannous chloride or boron trifluoride etherate in tetrahydrofuran gives 1,3-dithianes in high yields. The reaction of acids with thexylphenylth...

A semi-automatic method for the simultaneous determination of the sequence and the d/l-configuration of amino acids in peptides is reported. The automated sequencing program was set up based both on the yield in the cyclization/cleavage reaction with 40 mmol dm23 boron trifluoride (BF3) etherate at 48 °C for 5 min and on the recovery of anilinothiazolinone(ATZ-) amino acids extracted with ethyl...