B-substituted group 1 phosphides: synthesis and reactivity.

1-Boryl-8-phosphinonaphthalenes 1-BCy 2 -8-PCl 2 -C 10 H 6 (1) and 1-BCy 2 -8-PPhCl-C 10 H 6 (2) were prepared and used as starting materials for the synthesis of B-substituted phosphides. The reduction of 1 and 2 by Mg provided neutral compounds [1-BCy-8-PCy-C 10 H 6 ] 2 (3) and [1-BCy 2 -8-PPh-C 10 H 6 ] 2 (4). Compound 3 represents the dimer of phosphinoborane 1-BCy-8-PCy-C 10 H 6 while complex 4 is a rare example of a discrete B ← P coordinated diphosphine. The reduction of 2 by Na or K in THF yielded B-substituted group 1 phosphides [Na(THF) 3 ] + [1-BCy 2 -8-PPh-C 10 H 6 ] - (5) and {[K(THF) 2 ] + [1-BCy 2 -8-PPh-C 10 H 6 ] - } ∞ (6), which structurally resembled bulky group 1 phosphides. Complex 5 showed easy activation of elemental chalcogens E (E = O, S, Se) to give B-substituted chalcogenophosphinites {[Na(THF) 2 ] + [1-BCy 2 -8-P(E)Ph-C 10 H 6 ]} 2 (E = O (7), S (8), Se (9)) as the products of chalcogen insertion into the P-Na bond. Importantly no oxidation to dichalcogenophosphinates was observed. Compound 5 is tolerant of the CO polar bonds in organic substrates and the reactions of 5 with 2,3-butanedione or an acyl chloride provided {[Na(THF) 2 ] + [1-BCy 2 -8-P{CHC(O)C(Me)O}Ph-C 10 H 6 ] - } 2 (10) and [1-BCy 2 -8-P{C(O) t Bu}Ph-C 10 H 6 ] (11). Finally, B-coordinated phosphatetrylenes [1-BCy 2 -8-P(SnL)Ph-C 10 H 6 ] (12) and [1-BCy 2 -8-P(PbL)Ph-C 10 H 6 ] (13) (L is {2,6-(Me 2 NCH 2 )C 6 H 3 } - ) were also prepared by substitution reactions of 5.