Reactions of 2-Alkoxy-4-oxo-5,6-benzo- 1,3,2-dioxaphosphorinanes with Imines. Synthesis and Steric Structure of 6,7-Benzo-1,4,2-oxazaphosphepine Derivatives

Cycloexpansion Reactions in Benzo[e]-1,3,2-diheterophosphorin-4-ones and 4-Oxo-1,3,2-dioxaphospholanes

“…17 Phosphepine (18) bearing a methoxy group at phosphorus is easily subjected to the methylation reaction to give an internal salt (21). The structure of ethyl derivative (19) was confirmed by X-ray diffraction as shown in Figure 8. The heterocycle of the molecule has a distorted boat conformation with a pseudoaxial ethoxy-group and pseudoequatorial phosphoryl group.…”

“…The conformation of the six-membered heterocycle is a The cyclic phosphorylated derivatives of hydroxynicotinic acid, hydroxypicolinic acid, and phenylanthranycic acid (15)(16)(17) form the new phosphepine heterocycles (18)(19)(20) with hexafluoroacetone (Scheme 9). Dioxaphosphepine's fragments are fused with the pyridine moiety in the molecules (18,19). 17 Phosphepine (18) bearing a methoxy group at phosphorus is easily subjected to the methylation reaction to give an internal salt (21).…”

“…The high reactivity of imines to salicylphosphite (1) 19 The compounds containing a fluorinated substituent at phosphorus are more reactive than ones with a methoxy group. Under these conditions phosphite with a methoxy radical does not exhibit any evidence of interaction with imines, at least during one month.…”

Reactions of 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepin-5-one with phenanthrenequinone and dibenzoyl

“…They are capable of being involved in cascade reactions with activated carbonyl compounds, Schiff bases, and ylidene derivatives of dicarbonyl compounds. In these reactions, the carbonyl group can participate in one or another step of the cascade process, leading to the formation of 1,3,2-dioxa(oxaza)-and 1,4,2-dioxa-(oxaza)phosphepines, 1,2-oxaphospholanes, and other difficultly accessible compounds [5][6][7][8][9][10][11][12].…”

“…They are capable of being involved in cascade reactions with activated carbonyl compounds, Schiff bases, and ylidene derivatives of dicarbonyl compounds. In these reactions, the carbonyl group can participate in one or another step of the cascade process, leading to the formation of 1,3,2-dioxa(oxaza)-and 1,4,2-dioxa-(oxaza)phosphepines, 1,2-oxaphospholanes, and other difficultly accessible compounds [5][6][7][8][9][10][11][12].We recently showed that cyclic phosphorus(III) derivatives having an activated carbonyl group in the γ-position with respect to the phosphorus atom, e.g., 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepin-5-one (I), also undergo cascade transformations by the action of trichloroacetaldehyde and hexafluoroacetone. As a result, cage-like propeller phosphorane with a phosphorus-carbon bond (structure II) [13,14] or spiran structure III is formed; in the latter structure, the γ-carbonyl carbon atom becomes a spiro atom [15] (Scheme 1).…”