Details

Autor(en) / Beteiligte

• LaFortune, James H. W.
• Trofimova, Alina
• Cummings, Haley
• Westcott, Stephen A.
• Stephan, Douglas W.

Titel

Phosphinoboration of Diazobenzene: Intramolecular FLP Synthon for PN2B‐Derived Heterocycles

Ist Teil von

• Chemistry : a European journal, 2019-09, Vol.25 (54), p.12521-12525

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2019

Quelle

Wiley(RISS)

Beschreibungen/Notizen

• Phosphinoboration of diazobenzene with Ph2PBR′2 cleanly affords products of the form Ph2P(PhNNPh)BR′2 (2: R′2=catechol, cat; 4: R′2=phenanthrenediol, quin) and shows evidence of Ph2P(PhNNPh)Bpin 7 (pin: pinacol). The mechanism of these reactions was probed computationally and shown to proceed via intermediates involving a diazobenzene‐adduct of the boron center of the PB reagent. The resulting PNNB species 2 and 4 are shown to be frustrated Lewis pairs (FLPs). Despite the presence of weakly Lewis acidic boron centers, these species react with diazobenzene. Additionally, the FLP reactivity of 2 was further probed with 4‐phenyl‐1,2,4‐triazole‐3,5‐dione, 1,10‐phenanthroline‐5,6‐dione, and benzyl azide to give unique five‐, six‐, and eight‐membered heterocyclic rings. Thus, phosphinoboration provides a new avenue to FLPs in which donor and acceptor sites are linked by nitrogen atoms. Phosphinoboration leads to FLP formation: The products of the phosphinoboration of diazobenzene, Ph2P(PhNNPh)(BR′2) (2: R′2=catechol, cat; 4: R′2=phenanthrenediol, quin), are formed through a mechanism involving intermediate diazobenzene–PB adducts. These products are shown to act as frustrated Lewis pairs (FLPs) to give unique five‐, six‐, and eight‐membered heterocyclic rings.