Utilization of the Thorpe–Ingold Effect in the Synthesis of Cyclooctanoid Ring Systems via Anionic 6-<i>exo</i>-<i>dig</i> Cyclization/Claisen Rearrangement Sequence
作者:Weston C. DeLomba、Elizabeth A. Stone、Kimberly A. Alley、Victoria Iannarone、Emily Tarsis、Sami Ovaska、Timo V. Ovaska
DOI:10.1021/acs.joc.0c01132
日期:2020.8.7
demonstrate a facile approach for the synthesis of gem-disubstituted cyclooctanoids, a motif found in several biologically active compounds. Appropriately substituted 1-alkenyl-5-pentyn-1-ols bearing gem-dialkyl substituents at either the C2, C3, or C4 position serve as useful precursors to a number of cyclooct-4-enone derivativesvia a tandem, microwave-assisted oxyanionic 6-exo-dig cyclization/Claisen
We describe herein a new synthesis of enantiopure alkylidene 1,1-bis-p-tolyl-sulfoxides (5), based on a two-steps sequence. The first one involves the alkylation of the lithium anion of the (S,S)-bis-p-tolylsulfinylmethane (1) with aldehydes. The second one consists in a mild dehydration of the sulfinyl alcohols 3 and 4 with the morpho CDI reagent. Some features (reactivity, diastereoselectivity) of the alkylation reaction are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.