Abstract
Nap-Phos, representing a new naphthyl-phenyl biaryl-type phosphine ligand class and available by a short synthesis (4 steps, 71% overall yield), effectively catalyzes the Suzuki-Miyaura (including highly hindered cases), hydrodehalogenation, and Heck reactions.
Key words
cross-coupling - Suzuki-Miyaura - homogenous catalysis - Heck reaction - phosphorus ligand - hindered biaryls - dehydrohalogenation
References and Notes
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6 solution. Crystallographic data (excluding structure factors) for the structure of 4 have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-609270. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK [fax: +44(1223)336033; e-mail: deposit@ccdc.cam.ac.uk).
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[6a ]
Nap-Phos: (98%); entry 3: S-phos (82%),
[6a ]
Nap-Phos: (76%); entry 4: S-phos (86%),
[6a ]
Nap-Phos (70%).
24 A preliminary PM3 modeling study shows a low racemization barrier (20 kcal/mol) for Nap-Phos which precludes its use as a chiral ligand in cross coupling reactions under conditions described herein. Few chiral non-racemic atropisomeric ligand motifs are known. For discussion, see ref. 14c.