Phosphine ligands have played a supporting role in the success of many transition metal catalyst systems. They enhance activity, selectivity, and stability. Tri-t-butylphosphine has long been the most electron releasing alky phosphine ligand for transition metals. However, a very electron rich ligand with short term air stability has emerged to fill a void between trialkyl phosphines and their more electron donating N-heterocyclic carbene cousins. Sold in collaboration with the Green Centre, Strem Chemicals is pleased to report the commercial availability of the phosphine ligand, Tris(1-adamantyl)phosphine, 97%(15-0935).
Developed at Princeton University in the laboratory of Brad Carrow and coworkers, this remarkable phosphine is air- stable as solid for short time periods, decorated with a sterically demanding, rigid C10 cage, adamantly group as the only substituent. Spectroscopic data reveal that the ligand is benefiting from the polarizability inherent to large hydrocarbyl groups. It exhibits unexpected electron releasing character that surpasses other alkylphosphines falling within a range previously dominated by N- heterocyclic carbenes. The result is a surprisingly stable phosphine ligand which can bind to metals such as palladium to be used in Suzuki-Miyaura couplings in making drug intermediates. Dramatic effects in catalysis are also accessible now by using PAd3 as a ligand during Suzuki- Miyaura cross- coupling of chloro(hetero) arenes. Forty examples are now reported using low Pd loading, including late- stage functionalization of commercial drugs.1 Exceptional space- time yields are demonstrated for the syntheses of industrial precursors to valsartan and boscalid from chloroarenes with ∼2 × 104 turnovers in 10 minutes. J. Am. Chem. Soc., 2016, 138, 639
Products mentioned in this blog and related products:
15-0935: Tris(1-adamantyl)phosphine, 97% [897665-73-5]
15-1092: N-[2-(di-1-adamantylphosphino)phenyl]morpholine, 98% Mor-DalPhos [1237588-12-3]
15-1090: 2-(Di-1-adamantylphosphino)dimethylaminobenzene, 97% Me-DalPhos [1219080-77-9]
15-0483: Butyldi-1-adamantylphosphine, min. 95% [cataCXium® A] [321921-71-5]
15-0038: Benzyldi-1-adamantylphosphine, min. 85% [cataCXium® ABn] [395116-70-8]
15-5810: Tri-t-butylphosphine, 99% [13716-12-6]
15-6000: Tri-t-butylphosphonium tetrafluoroborate, 99% [131274-22-1]