Publications [#231785] of Steven W. Baldwin

Journal Articles

  1. Ireland, RE; Baldwin, SW; Welch, SC, "Experiments Directed toward the Total Synthesis of Terpenes. XVII. Development of Methods for the Synthesis of Pentacyclic Triterpenes Based on a Mechanistic Interpretation of the Stereochemical Outcome of the Friedel–Crafts Cyclialkylation Reaction", Journal of the American Chemical SocietyMarch,, 1972, 94(6), 2056-2066, American Chemical Society (ACS) [doi].
    (last updated on 2024/04/19)

    Abstract:
    The α-methylene ketone 11 was prepared and found to undergo conjugate addition with m-methoxybenzylmagnesium chloride with great facility. The initial adduct was trapped with acetic anhydride, and the resulting enol acetate 12 was used either in methylation experiments to prepare vicinal-dimethylated ketone 13 or to generate the ketone 16 by saponification. Cyclization of the former ketone 13 with polyphosphoric acid served to delineate a route to β-amyrin-type triterpenes, while polyphosphoric acid cyclization of the product from methyllithium and the latter ketone 16 provided a means for the construction of friedelin-type triterpenes. The stereochemical outcome of the latter cyclialkylation reaction is interpreted in the light of recent mechanistic concepts. © 1972, American Chemical Society. All rights reserved.