exothermically

Adverb

 * 1) In an exothermic manner
 * Aldrichimica Acta Volume 30 No 4 (pdf) from Sigma-Aldrich
 * The fused cyclobutenomaleimide is much more reactive than Smith’s diene; it reacts with cyclopentadiene exothermically at room temperature to yield the extended isomer as the major cycloaddition product.