Stereochemical Behavior of Pairs of P-stereogenic Phosphanyl Groups at the Dimethylxanthene Backbone

0555181 - ÚACH 2023 RIV DE eng J - Journal Article
Škoch, Karel - Daniliuc, C. G. - Mueller, M. - Grimme, S. - Kehr, G. - Erker, G.
Stereochemical Behavior of Pairs of P-stereogenic Phosphanyl Groups at the Dimethylxanthene Backbone.
Chemistry - A European Journal. Roč. 28, č. 20 (2022), č. článku e202200248. ISSN 0947-6539. E-ISSN 1521-3765
Institutional support: RVO:61388980
Keywords : boron * inversion * methylene phosphonium * phosphorus * stereogenic phosphorus
OECD category: Inorganic and nuclear chemistry
Impact factor: 4.3, year: 2022
Method of publishing: Limited access
https://doi.org/10.1002/chem.202200248

The P-stereogenic bis(phosphanes) 7 and 9, featuring pairs of P(Mes)-ethynyl or vinyl substituents at the dimethyl xanthene backbone show rather low barriers of stereochemical inversion at phosphorus. pi-Conjugative effects are probably causing these low inversion barriers. Compound 7 reacted with B(C6F5)(3) to form the nine-membered heterocyclic product 10, featuring a [P]-C equivalent to C-B(C6F5)(3) substituent. Compound 7 was converted to the bis[P(Mes)vinyl] xanthene derivative 9, which gave the zwitterionic P(H)(Mes)-CH=CH-B(C6F5)(3) containing product 16 upon treatment with B(C6F5)(3). Thermally induced epimerization barriers at phosphorus of ca. 20 to 27 kcal mol(-1) were calculated by DFT for the alkenyl- and alkynyl-P derived systems 6 to 9, 15 and 16 and experimentally determined for the examples 7 and 16.
Permanent Link: http://hdl.handle.net/11104/0329707


Research data: CCDC, Wiley onlinelibrary