Cyclic peroxides. 52. .alpha.-Peroxylactones via dehydrative cyclization of .alpha.-hydroperoxy acids

Acylation Mechanisms of DMSO/[D6]DMSO with Di‐tert‐butylketene and Its Congeners

“…A second novel variant concerns an initiating DMSO addition to the ketene t Bu 2 C=C=O, followed by an intermolecular proton‐transfer step from carboxylic acids that contributes to the overall reaction rate, whereas the subsequent steps do not contribute. The latter mechanistic variant seems to be without precedence,4,48,49 because the previously reported reactions of two other stable ketenes with sulfoxides were apparently not conducted in this way: (i) The initiating zwitterionic intermediate formulated50 for Cl 2 C=C=O reacting with α,β‐unsaturated sulfoxides48,51 is thought to rearrange through a (formal) [3,3]‐sigmatropic migration; (ii) Ph 2 C=C=O (reported52 to be unsusceptible to protonation at C‐2) and acidified DMSO follow a different route to produce benzilic acid;53 the corresponding product t Bu 2 C(OH)CO 2 H expected from ketene 2 is known54 but could not be found in the present investigations.…”

Bioorganic Chemistry

“…This compound is decarboxylated by the enzyme luciferase (569). Luminescent bacteria, worms, and the amazing firefly have all been the objects of the biochemists' curiosity.…”

Bioorganic Chemistry

“…A clue comes from the fact that chemiluminescence is very common when O 2 is used as an oxidant and extraction of luminous materials from organisms showed that one of the active principle in the firefly system is luciferin. This compound is decarboxylated by the enzyme luciferase (298). This enzymatic oxygeneation by carbanion attack on O 2 followed by decarboxylation occurs without conjugated-cofactor assistance and is thus 416 7: Coenzyme Chemistry different from the mode of action of bacterialluciferase, a flavin-dependent monooxygenase (299).…”