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

Abstract

Reactions of 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-benzodioxaphosphepin-5-one with 9,10-phenanthrenequinone and dibenzoyl gave hydrolytically unstable spirophosphoranes with five-and seven-membered rings, 2-phenyl-4,4-bis(trifluoromethyl)-4,5-dihydrospiro [[1,3,2]benzodioxaphosphepine-2,2′-phenanthro[9,10-d][1,3,2]dioxaphosphol]-5-one and 2,4′,5′-triphenyl-4,4-bis(trifluoromethyl)-4,5-dihydrospiro [[1,3,2]benzodioxaphosphepine-2,2′-[1,3,2]dioxaphosphol]-5-one. The structure of the first of these was proved by X-ray analysis. R 1 = R 2 = CF 3 ; R 1 = CCl 3 , R 2 = H. Tervalent phosphorus derivatives are key precursors of various organophosphorus compounds with different coordination numbers of the phosphorus atom [1][2][3][4]. This is related to accessibility of lone electron pair on the phosphorus atom and thermodynamic favorability for the formation of phosphoryl compounds. Cyclic phosphorylated derivatives of salicylic acid having a fairly reactive carbonyl group in the β-position with respect to the phosphorus atom occupy a specific place among P(III) compounds. 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).