B(C F ) -Enabled Synthesis of a Cyclic cis-Arsaphosphene.

The synthesis and characterization of an (arsino)phosphaketene, As(PCO){N(Dipp)} (Dipp=2,6-diisopropylphenyl) is reported along with its subsequent reactivity with B(C F ) . When reacted in a stoichiometric ratio, B(C F ) drove the insertion of the P=C bond of the phosphaketene into one of the As-N bonds of the arsino functionality, affording an acid-stabilized, seven-membered, cyclic arsaphosphene. In contrast, when catalytic amounts of B(C F ) were employed, dimeric species, which formed through a formal [2+2] cycloaddition of the cyclic arsaphosphene, were generated. The cyclic arsaphosphene product represents the first example of such a compound in which the two substituents are arranged in a cis-configuration.