Benzopyran derivativesR 0350 DOI: 10.1002/chin.201137140

Hydroxyl-Directed C—H Carbonylation Enabled by Mono-N-Protected Amino Acid Ligands: An Expedient Route to 1-Isochromanones. — Phenethyl alcohol de-rivatives (I) and (IV) undergo a C—H carbonylation reaction under Pd(II) catalysis in the presence of protected amino acids as ligands. Functional groups such as bromine and methoxy substituents are tolerated. meta-Substituted substrates, viz. (Ih), undergo regioselective insertion at the less hindered position. However, primary and secondary alcohols are less suitable educts and give the product in lower yield. In general, the iso-chromanone motif is a common structural element in biologically active natural prod-ucts such as histamine release inhibitor (Vc), which can be synthesized in one step from the commercially available precursor. — (LU, Y.; LEOW, D.; WANG, X.; ENGLE, K. M.; YU*, J.-Q.; Chem. Sci. 2 (2011) 5, 967-971, http://dx.doi.org/10.1039/c0sc00633e ; Dep. Chem., Scripps Res. Inst., San Diego, La Jolla, CA 92037, USA; Eng.) — K. Wilckens

37- 140

ChemInform 2011, 42, issue 37 © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim