3-Bromo-5-methylene-2 -furanone

Bromo-5-methylene-2(5//)-furanone 133 was obtained from the /3-angelica lactone 129 by using mild simple methods that combine bromination and dehy-drobromination or debromination processes accomplished in a convenient order, as illustrated in Scheme 41 (94T12457). 

Thermal cycloadditions of butadiene to 3-bromo- 133 and 3-methoxy-5-methylene-2(5//)-furanones 220 were studied (95TL749). These systems contain substituents at C3 capable of stabilizing also a possible radical intermediate, influencing hereby the rate and/or the course of the reaction. Thus, the reaction of 133 and 220, respectively, with butadiene at 155°C afforded mixtures of the expected 1,4-cycloadducts 221 and 222, respectively, and of the cyclobutane derivatives... 

C5H5BrS 3-bromo-4-methylthiophene 30318-99-1 454.15 39.497 1,2 4549 C5H602 dihydro-3-methylene-2 3H)-furanone 547-65-9 412.82 35.575 2... 

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