Functionalization of Bis-Diazaphospholene P-P Bonds with Diverse Electrophiles

Abstract

<p>Readily prepared bis-diazaphospholenes are shown to react with several classes of electrophiles, resulting in cleavage of the phosphorus-phosphorus bond and formation of functionalized diazaphospholenes. Phosphorus – sp<sup>3</sup> or sp<sup>2</sup> carbon and phosphorus – sulfur bonds were formed using this protocol. Experimental evidence with aryl and alkyl halides suggests the intermediacy of radicals in some cases, however other evidence suggests either radical or polar mechanisms may be operative for certain substrates, with a dependence on reaction conditions. In some cases, the substituted diazaphospholenes can transfer the substituent to electrophiles via previously unknown reactions. These results show diazaphospholene dimers are potent participants in radical chemistry at room temperature without requiring chemical initiators.</p>

Chemoselective catalytic hydrodefluorination of trifluoromethylalkenes towards mono-/gem-di-fluoroalkenes under metal-free conditions

“…Building on our previous work 59 , we envisioned that diazaphospholenes of super hydricity 60 – 62 may provide a good chance to realize HDF of trifluoromethylalkenes via an S N 2’ path 63 . A preliminary attempt indicated that the reaction of α-trifluoromethyl-styrene 2a with diazaphospholene 1 primarily gave the hydrophosphination intermediate A .…”

Stay positive: catalysis with 1,3,2-diazaphospholenes

“…Notably, during the drafting of this manuscript, two reports, detailing the use of DAP-hydrides in radical reactions appeared. 30,31 These results open the possibility for a complementary reactivity mode involving hydrogen radicals instead of the hydride paradigm. Whereas both reactions utilise a stoichiometric amount of DAP-hydride, it remains to be investigated whether these processes can be affected using a catalytic amount of the DAP.…”