Cyclic Carboxylic Acid‐Organoboron Compounds with BHB Bridge Bonding

Abstract

la, however, is not oxidized by y-picoline N-oxide"] up to 110°C. But reaction of the same reagent with 3 leads, exclusively via BCVinyl oxidation, to high yields of 2,6-diethyl-4,4,5-trimethyI-4H-l,3,2-dio~asilaborinine~***~ 8. In contrast 3 reacts only slightly regioselectively with trimethylamine N-oxide, with formation of 70% 8 and 30% 9.The formation of the various 02and N-oxide products from the unsaturated five-membered rings 1 and 3 demonstrates that the atomic grouping around the acceptor atom Angew. Chem. Int. Ed. Engl. 23 (1984) No. 2 0 Verlag Chemie GmbH, 0-6940 Weinheim, 1984 0570-0833/84/0202-0155 $02.50/0