An Improved Total Synthesis of (±) - Podocarpic Acid by a Cyclialkylation Route

Abstract

Abstract A number of total syntheses of (±) - podocarpic acid (i) have been described1 King, King and Topliss2 first identified one of the products from nonstereo-selective cyclization of (4) with polyphosphoric acid as (±)- ethyl-O-methylpodocarpate (2) and correlated that with the corresponding acid (3), prepared in an extremly poor yield (ca 0.4%)3 by Bhattacharyya3, and Haworth and Moore4 by cyclization of (5) with a mixture of sulfuric acid and acetic acid. More recently Mancini, Fringuelli and Taticchi5 prepared (3) (in 4.8% yield) by repeating Howorth1 s cyclization of (4). In continuation of our studies on cyclialky-