An unusual reaction of 2‐ethoxyethenylphosphonic dichloride with resorcinol and its derivatives: Synthesis of bicyclic phosphonates with endocyclic P–C bond

Modification of Bicyclic Phosphonates Based on Resorcinols and Its Derivatives via the Mannich Reaction

“…Compounds 1-3 were synthesized by condensation of 2-ethoxyethenylphosphonic dichloride with resorcinol and its derivatives methodology previously reported [21,22]. The mixture of (0.5 g; 1.5 mmol) bicyclic phosphonate 1, (0.27 g; 3 mmol) morpholine 4b, and (0.09 g; 3 mmol) paraformaldehyde in 20 mL benzene was kept under reflux with the Dean-Stark adapter for 12 h (until the evolution of water stops).…”

Synthesis of 1,2-oxaphosphinane 2-oxides and 1,2-oxaphosphinine 2-oxides: δ-phosphonolactones and δ-phosphinolactones

“…After the acid-catalyzed aromatization and elimination of EtOH, benzylic carbocations formed and further the Friedel–Crafts alkylation took place with the second molecule of benzene-1,3-diols, affording 4-aryl-2-chloro-3,4,4 a -trihydrobenzo[ e ][1,2]oxaphosphinin-7-one 2-oxides, which further underwent intramolecular phosphonylation to give rise to the final product 3,9-dihydroxy-12 H -6,12-methanodibenzo[ d , g ][1,3,2]dioxaphosphocine 6-oxides. 92 The method was also applied in the synthesis of 2-hydroxybenzo[ e ][1,2]oxaphosphinine 2-oxide from 3-methoxyphenol and ( E )-(2-ethoxyvinyl)phosphonic dichloride. They first generated 3-methoxyphenyl ( E )-(2-ethoxyvinyl)phosphonochloridate in the presence of triethylamine.…”

“…The reaction process was suggested as: after phosphonylation of benzene-1,3-diols with (E)-(2-ethoxyvinyl) phosphonic dichloride, an intramolecular Michael addition occurred to generate 2-chloro-4-ethoxy-3,4,4a-trihydrobenzo[e][1,2] oxaphosphinin-7-one 2-oxides. After the acid-catalyzed aromatization and elimination of EtOH, benzylic carbocations formed and further the Friedel-Crafts alkylation took place with the second molecule of benzene-1,3-diols, affording 4-aryl-2-chloro-3,4,4atrihydrobenzo[e][1,2]oxaphosphinin-7-one 2-oxides, which further underwent intramolecular phosphonylation to give rise to the final product 3,9-dihydroxy-12H-6,12-methanodibenzo[d,g] [1,3,2]dioxaphosphocine 6-oxides 92. The method was also applied in the synthesis of 2-hydroxybenzo[e][1,2]oxaphosphinine 2-oxide from 3-methoxyphenol and (E)-(2-ethoxyvinyl)phosphonic dichloride.…”

Novel Naphthol‐Based Bicyclic Phosphonates

“…Earlier, we reported on a single‐step synthesis of new cyclic phosphonates based on the condensation of 2‐ethoxyvinyldichloro‐phosphonate 1 with resorcinol and its derivatives in dioxane in the presence of trifluoroacetic acid (TFA), and the scheme of their formation was suggested .…”