Srinivasan Ganapathy

The photo-Arbuzov rearrangement of dimethyl 9-anthrylmethyl phosphite and the photodimerization of the corresponding phosphonate†

Upon irradiation, 9-anthrylmethyl phosphite (2) undergoes the photo-Arbuzov rearrangement to give the corresponding phosphonate 3. Prolonged irradiation led to the clean formation of the centrosymmetric, head to tail, [4 + 4] photocycloaddition product 4 as indicated by X-ray crystallographic analysis. The same photodimer results on irradiation of phosphonate 3 itself in solution or in the solid phase. Phosphite 2 does not undergo photodimerization to 6.

Effect of placement of phosphorus in a ring on the triplet-sensitized photorearrangement of 2-phenylallyl phosphites

Abstract The triplet-sensitized photorearrangement of 2-phenyllayl phosphite 4 is of the order 50–100 times less efficient than that for its acyclic counterpart, 1. This surprising effect can be understood in terms of the influence of the spiro ring system of 10 on the rate of its conversion to thermodymanically more stable 11 from which phosphonate 12 is formed.

Radical-Pair Intermediates in the Photolysis of Arylmethoxy Groups Attached to Three- Coordinate Phosphorus

Abstract. Stereochemical and product studies of the photochemistry of the title compounds is interpreted in terms of concerted as well as singlet and triplet radical-pair mechanisms.