Chelating Phosphorus-An O, C, O-Coordinating Pincer-Type Ligand Coordinating P and P Centres.

The sequence of reactions of the phosphorus-containing aryllithium compound 5-t-Bu-1,3-[(P(O)(O-i-Pr) ] C H Li (ArLi) with Ph PCl, KMnO , elemental sulfur and elemental selenium, respectively, gave the aryldiphenylphosphane chalcogenides 5-t-Bu-1,3-[(P(O)(O-i-Pr) ] C H P(E)Ph (1, E=O; 2, E=S; 3, E=Se). Compound 1 partially hydrolysed giving [5-t-Bu-1-{(P(O)(O-i-Pr) }-3-{(P(O)(OH) }C H ]P(O)Ph (4). The reaction of ArLi with PhPCl provided the benzoxaphosphaphosphole [1(P), 3(P)-P(O)(O-i-Pr)OPPh-6-t-Bu-4-P(O)(O-i-Pr) ]C H P (5i) as a mixture of the two diastereomers. The oxidation of 5i with elemental sulfur gave the benzoxaphosphaphosphole sulfide [1(P), 3(P)-P(O)(O-i-Pr)OP(S)Ph-6-t-Bu-4-P(O)(O-i-Pr) ]C H (5) as pair of enantiomers P1(R), P3(S)/P1(S), P3(R) of the diastereomer (RS/SR)-5 (5b). The aryldiphenylphosphane 5-t-Bu-1,3-[(P(O)(O-i-Pr) ] C H PPh (6) was obtained from the reaction of the corresponding aryldiphenylphosphane sulfide 2 with either sodium hydride, NaH, or disodium iron tetracarbonyl, Na Fe(CO) . The oxidation of the aryldiphenylphosphane 6 with elemental iodine and subsequent hydrolysis yielded the aryldiphenyldioxaphosphorane 9-t-Bu-2,6-(OH)-4,4-Ph -3,5-O -2,6-P -4λ -P-[5.3.1.0]-undeca-1(10),7(11),8-triene (7). Both of its diastereomers, (RR/SS)-7 (7a) and (RS/SR)-7 (7b), were separated as their chloroform and i-propanol solvates, 7a⋅2CHCl and 7b⋅i-PrOH, respectively. DFT calculations accompanied the experimental work.