Formation and reactions of active five-membered phosphane/borane frustrated Lewis pair ring systems. Issue 13 (2nd March 2018)

• Record Type: Journal Article
• Authors: Dong, Shunxi; Wang, Long; Wang, Tongdao; Daniliuc, Constantin G.; Brinkkötter, Melanie; Eckert, Hellmut; Kehr, Gerald; Erker, Gerhard
• Is Part Of: Dalton transactions. Volume 47:Issue 13(2018)
• Page Start: 4449
• Page End: 4454
• Publication Date: 2018-03-02
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt00672e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The five-membered P/B FLP ring systems featuring very bulky Tipp or Mes* aryl groups at phosphorus undergo addition reactions with organic π-reagents. Abstract : The reactive five-membered frustrated P/B Lewis pair6a was generated from Tipp-P(vinyl)2 (Tipp: 2, 4, 6-triisopropylphenyl) by a series of anti-Markovnikov and Markovnikov hydroboration reactions. The in situ generated compound dimerized to give7a under kinetic control and the dimer pair8a /9a under thermodynamic control. The Mes*-P(vinyl)2 analogue (Mes*: 2, 4, 6-tri- tert -butylphenyl) reacts in a similar way, but in this case the thermodynamic dimers are observed at r.t. whereas the monomer6b is the dominant species at 80 °C in solution. It is an active dihydrogen splitting reagent. The in situ generated monomeric five-membered P/B FLPs undergo addition reactions to various organic π-reagents. With benzaldehyde or phenylacetylene this gave the respective zwitterionic heteronorbornene or -norbornadiene type products, the latter with liberation of ethylene.