Total Synthesis of Gramistilbenoids A, B, and C

DipeshS. Harmalkar, Qili Lu, Kyeong Lee

Index: 10.1021/acs.jnatprod.7b00865

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Abstract

Stilbenes are biologically active metabolites of plants that have the potential to attenuate a broad range of human diseases. Gramistilbenoids are a class of natural products with a stilbene skeleton, isolated from the bamboo orchid (Arundina graminifolia), and with significant cytotoxicity against cancer cell lines (NB4, A549, SHSY5Y, PC3, and MCF7). These are the first identified naturally occurring diphenylethylenes to possess a hydroxyethyl unit. However, some of these compounds are not abundant in nature, and thus, their synthesis is advantageous. This paper reports the first synthesis of gramistilbenoids A (1), B (2), and C (3), with overall yields of 10, 2, and 8% respectively. These natural products were synthesized using key reactions, such as Horner–Wadsworth–Emmons olefination, Stille coupling, and hydroboration–oxidation.