ORTHOMANGANATED ARENES IN SYNTHESIS .9. PHOTOCHEMICAL-REACTIONS OF ALKYNES WITH ORTHOMANGANATED TRIPHENYL PHOSPHITE

The reaction of othomanganated triphenyl phosphite, (PHO)2P(OC6H4)Mn(CO)4 (1) with alkynes (C2Ph2, C2(COOME)2, PhCCH, Me3SiCCH) under UV irradiation gives products derived from insertion of the alkyne into the MN-C bond. The main products are the seven-membered metallacyclic species (PHO)2P(OC6H4)C(R2)=C(R1)Mn(CO)4 (2) (both regioisomers for the unsymmetrical alkynes). Also obtained from the C2Ph2 reaction was (PHO)2POC6H4)C(Ph)=C(Ph)C(O)Mn(CO)3 (4) formed by insertion of both C2Ph2 and CO, and a compound {2,6-[PhCH=C(Ph)]2C6H3O}{2-[PhCH=C(Ph)]C6H4O}POC6H4)Mn(CO)4 (3) derived from 1 by substitution with -C(Ph)=C(Ph)H groups at three of the ortho sites on the unmetalated phenoxy rings by a sequence of insertion/demetalation steps. A metal acetylide, PhCCMn(CO)3[P(OPh)3]2 (6) was also isolated from the reaction with PhCCH. Crystal structures are described for 2e (R1 = Ph, R2 = H; triclinic, space group P1BAR, a = 10.619 (11) angstrom, b = 10.896 (6) angstrom, c = 11.619 (8) angstrom, alpha = 77.68, beta = 80.81 (7)-degrees, gamma = 80.31 (6)-degrees, Z = 2, 2772 reflections, R = 0.039), 3 (monoclinic, space group P2(1)/n, a = 10.743 (6) angstrom, b = 27.456 (23) angstrom, c = 17.536 (14) angstrom, beta = 104.86 (5)-degrees, Z = 4, 3941 reflections, R = 0.0599), 4 (monoclinic, space group P2(1)/n, a = 9.907 (6) angstrom, b = 18.458 (11) angstrom, c = 16.539 (8) angstrom, beta = 94.35 (4)-degrees, Z = 4, 2565 reflections, R = 0.104), and 6 (orthorhombic, space group P2(1)2(1)2(1), a = 19.888 (6) angstrom, b = 19.732 (8) angstrom, c = 10.467 (4) angstrom, Z = 4, 3085 reflections, R = 0.0523).