Suzuki–Miyaura Cross-Coupling Aryl borate 3a, the second component required for Suzuki–Miyaura cross-coupling, was prepared starting from
l-tyrosine (Scheme 4). Methyl ester formation, as shown, followed by protection of the amino group as its Cbz derivative under standard conditions
afforded phenol 17 in quantitative yield. Subsequent O-methylation of 17 with Me2SO4 in the presence of LiOH in THF provided 18 in 86% yield.17
Selective iodination of 18 at the 3-position, ortho to the methoxy group, was accomplished in high yield with I2/AgSO4 in methanol
(see compound 19).18 The required aryl borate 3a was obtained from 19 in 95% yield following Miyaura’s protocol.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2507741/
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