Convenient Access to Arylated Spirocyclic Bisphosphonates

Abstract

The synthesis of P-arylated spirocyclic bisphosphonates is described. The title compounds were generated through a process that combined transesterification with a palladium catalyzed P-arylation. The cross-coupling step could be carried out at room temperature using aryl iodides, while analogous reactions involving aryl bromides required heating. Nitrogen, oxygen, and sulfur containing heterocycles were also success-fully incorporated into the framework. Using this approach 20 new arylated compounds were generated bearing a range of electrophiles and functional groups. For the more reactive aryl iodides, the catalyst loading could be decreased to 0.3 % Pd per PÀH group in scaled-up versions of the method. The two-step process does not require the use of chlorophosphorus reagents.

Synthesis of Spirocyclic Diphosphite-Supported Gold Metallomacrocycles via a Protodeauration/Cyclization Strategy: Mechanistic and Binding Studies

“…The title compound was made by a modification of the literature procedure . A round-bottom flask was charged with pentaerythritol (1.00 g, 7.34 mmol) and a magnetic stirring bar.…”

“…71 1 was generated by a modification of the literature procedure as described below. 21 DMSO-d 6 was dried over activated molecular sieves (3 Å). CDCl 3 was dried over CaH 2 and distilled immediately prior to use.…”

“…The title compound was made by a modification of the literature procedure. 21 A round-bottom flask was charged with pentaerythritol (1.00 g, 7.34 mmol) and a magnetic stirring bar. After the flask was sealed with a septum and the atmosphere was exchanged with nitrogen, diphenyl phosphite (3.00 mL, 15.7 mmol) and pyridine (10 mL) were added by syringe.…”

“…To this end, we surmised that the spirocyclic diphosphite (1, shown in Figure 1 in its hydrogen phosphonate form) and its derivatives could be effective "rigid" linkers for metallomacrocycles and MOFs. 21 Indeed, tertiary phosphites based upon a pentaerythritol core have been used to generate dinuclear complexes and coordination polymers. 22 One of the common methods used for the preparation of late-metal-containing metallomacrocycles and MOFs utilizes a metal precursor bearing a weakly coordinating ligand such as water, nitrate, or solvent.…”

“…To this end, we surmised that the spirocyclic diphosphite ( 1 , shown in Figure in its hydrogen phosphonate form) and its derivatives could be effective “rigid” linkers for metallomacrocycles and MOFs . Indeed, tertiary phosphites based upon a pentaerythritol core have been used to generate dinuclear complexes and coordination polymers .…”