CONFORMATIONS OF SATURATED 6-MEMBERED-RING PHOSPHORUS-HETEROCYCLES SYNTHESES AND X-RAY CRYSTAL-STRUCTURES OF 2 2-(DIMETHYLAMINO)-2-OXO-3-ARYL-5,5-DIMETHYL-1,3,2-OXAZAPHOSPHORINANES

The crystal and molecular structures have been determined for 2-(dimethylamino)-2-oxo-3-(4-fluorophenyl)-5. 5-dimethyl-l, 3, 2-oxazaphosphorinane, 1, and 2-(dimethylamino)-2-oxo-3-(4-dimethylaminophenyl)-5, 5-dimethyl-l, 3, 2-oxazaphosphorinane, 2. Compound 1 crystallizes in the monoclinic space group P2/c with eight molecules per unit cell (2 crystallographically independent molecules) of dimensions a = 17. 251(4) Å, b = 10. 822(3) Å. c = 18. 075(6) Å. and β = 118. 20(2)°. Compound 2 crystallizes in the monoclinic space group P21/a with Z = 4, a = 14. 148(7) Å, b = 6. 907(4) Å, c = 17. 210(6) Å. andβ = 94. 33(3)°. Full-matrix least-squares refinement of these structures converged at R = 0. 0469 and R = 0. 0581 for 1 and 2, respectively. Both compounds adopt chair conformations in the solid state with equatorially disposed dimethylamino substituents on phosphorus. © 1991 Taylor & Francis Group, LLC. All rights reserved.