Challenges in Catalytic Hydrophosphination.

Despite significant advances, metal-catalyzed hydrophosphination has ample room for discovery, growth, and development. Many of the key successes in metal-catalyzed hydrophosphination over the last decade have indicated what is needed and what is yet to come. Reactivity that is absent from the literature also speaks to the challenges in catalytic hydrophosphination.

Tin-catalyzed hydrophosphination of alkenes.

Simple tin derivatives, Cp*2SnCl2 (1) and Ph2SnCl2 (2), catalyze the hydrophosphination of alkene substrates with diphenylphosphine. Competitive dehydrocoupling to give Ph4P2 was observed, but this side reaction can be mitigated when the catalysis is conducted under an H2 atmosphere. Efforts to prepare stable tin bis(phosphido) compounds commonly resulted in decomposition to Ph4P2.

Zirconium-catalyzed intermolecular hydrophosphination using a chiral, air-stable primary phosphine.

Catalytic hydrophosphination of alkenes using a chiral, air-stable primary phosphine, (R)-[2'-methoxy(1,1'-binapthalen)-2-yl]phosphine, (R)-MeO-MOPH2, proceeds under mild conditions with a zirconium catalyst, [κ(5)-N,N,N,N,C-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH]Zr (1), to selectively furnish anti-Markovnikov, air-stable secondary phosphines or tertiary phosphines with slight modification of the protocol. An intermediate in the catalysis, [(N3N)Zr(R)-MeO-MOPH] (4), was structurally characterized.

Intermolecular zirconium-catalyzed hydrophosphination of alkenes and dienes with primary phosphines.

Catalytic hydrophosphination of terminal alkenes and dienes with primary phosphines (RPH2; R = Cy, Ph) under mild conditions has been demonstrated using a zirconium complex, [κ(5)-N,N,N,N,C-(Me3SiNCH2CH2)2NCH2CH2NSiMe2CH]Zr (1). Exclusively anti-Markovnikov functionalized products were observed, and the catalysis is selective for either the secondary or tertiary phosphine (i.e.