Monoselective o-C-H Functionalizations of Mandelic Acid and α-Phenylglycine
Navid Dastbaravardeh1, Tetsuya Toba1, Marcus E Farmer1
1Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States.
Abstract:
Pd-catalyzed C-H functionalization of mandelic acid and α-phenylglycine is reported. We have developed different protocols for the arylation, iodination, acetoxylation, and olefination of these substrates based on two different (Pd(II)/Pd(IV) and Pd(II)/Pd(0)) catalytic cycles. Four crucial features of these protocols are advantageous for practical applications. First, the α-hydroxyl and amino groups are protected with simple protecting groups such as acetates (Ac, Piv) and carbamates (Boc, Fmoc), respectively. Second, these protocols do not involve installation and removal of a directing group. Third, monoselectivity is accomplished. Fourth, no epimerization occurs at the vulnerable α-chiral centers.
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