TY - JOUR

T1 - Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids

T2 - A crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

AU - Lozovskiy, Stanislav V.

AU - Ivanov, Alexander Yu

AU - Vasilyev, Aleksander V.

N1 - Funding Information: This work was supported by the Russian Scientific Foundation (grant no. 18-13-00008). Spectral studies were performed at the Center for Magnetic Resonance, Center for Chemical Analysis and Materials Research, and Research Center for X-ray Diffraction Studies of Saint Petersburg State University, Saint Petersburg, Russia. Publisher Copyright: © 2019 Lozovskiy et al.; licensee Beilstein-Institut. License and terms: see end of document. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2019/7/8

Y1 - 2019/7/8

N2 - 3-Methylbuta-1,2-dien-1-ylphosphonic acid derivatives (phosphorylallenes) [X2(O=)P-CR=C=CMe2, X = Cl, OMe, NR2, or SAr] undergo intramolecular cyclization into the corresponding 1,2-oxaphospholium ions in the Brønsted superacid TfOH. These cations have been thoroughly studied by means of NMR spectroscopy. The hydrolysis of superacidic solutions of these species afforded cyclic phosphonic acids and other phosphorus-containing compounds. Contrary to Brønsted acids, 3-methylbuta-1,2-dien-1-ylphos-phonic dichloride [Cl2(O=)P-HC=C=CMe2] reacted with the Lewis acid AlCl3 in an intermolecular way forming noncyclic intermediates, which were investigated by NMR spectroscopy and DFT calculations. Hydrolysis of these species resulted in the formation of phosphoryl-substituted allyl alcohols and 1,3-butadienes. A strong coordination of the oxygen of the P=O group with AlCl3 prevented the formation of cyclic 1,2-oxaphospholium ions and played a crucial role in the different reactivity of such phosphorylallenes under the action of Brønsted or Lewis acids. Apart from that, the reaction of dichlorophosphorylallenes with arenes and AlCl3 led to products of hydroarylation of the allene system, phosphoryl-substituted alkenes and/or indanes. This is the first example of a Lewis acid-promoted intermolecular hydroarylation of allenes bearing electron-withdrawing substituents. Plausible reaction mechanisms have been proposed on the basis of the investigated reactions, and NMR analysis and DFT studies of the intermediate cationic species.

AB - 3-Methylbuta-1,2-dien-1-ylphosphonic acid derivatives (phosphorylallenes) [X2(O=)P-CR=C=CMe2, X = Cl, OMe, NR2, or SAr] undergo intramolecular cyclization into the corresponding 1,2-oxaphospholium ions in the Brønsted superacid TfOH. These cations have been thoroughly studied by means of NMR spectroscopy. The hydrolysis of superacidic solutions of these species afforded cyclic phosphonic acids and other phosphorus-containing compounds. Contrary to Brønsted acids, 3-methylbuta-1,2-dien-1-ylphos-phonic dichloride [Cl2(O=)P-HC=C=CMe2] reacted with the Lewis acid AlCl3 in an intermolecular way forming noncyclic intermediates, which were investigated by NMR spectroscopy and DFT calculations. Hydrolysis of these species resulted in the formation of phosphoryl-substituted allyl alcohols and 1,3-butadienes. A strong coordination of the oxygen of the P=O group with AlCl3 prevented the formation of cyclic 1,2-oxaphospholium ions and played a crucial role in the different reactivity of such phosphorylallenes under the action of Brønsted or Lewis acids. Apart from that, the reaction of dichlorophosphorylallenes with arenes and AlCl3 led to products of hydroarylation of the allene system, phosphoryl-substituted alkenes and/or indanes. This is the first example of a Lewis acid-promoted intermolecular hydroarylation of allenes bearing electron-withdrawing substituents. Plausible reaction mechanisms have been proposed on the basis of the investigated reactions, and NMR analysis and DFT studies of the intermediate cationic species.

KW - Aluminum chloride

KW - Cation

KW - Intermediate

KW - Oxaphospholium ions

KW - Phosphoryl group

KW - Phosphorylallenes

KW - Triflic acid

UR - http://www.scopus.com/inward/record.url?scp=85077668386&partnerID=8YFLogxK

U2 - 10.3762/bjoc.15.151

DO - 10.3762/bjoc.15.151

M3 - Article

AN - SCOPUS:85077668386

VL - 15

SP - 1491

EP - 1504

JO - Beilstein Journal of Organic Chemistry

JF - Beilstein Journal of Organic Chemistry

SN - 2195-951X

ER -