We have synthesized various types of acetals using 3-methyl-3-butenal and 2-alkenyl, furfuryl, benzyl, p-substituted benzyl, and 2-pentynyl alcohols. These acetals have given corresponding aldehydes after an acid catalytic reaction. Trifluoroacetic acid (CF3COOH) was the best catalyst. The best yield attained was 79% when 3-methyl-3-butenal di(trans-2-pentenyl) acetal was used as a substrate. We also demonstrated that this reaction proceeded via a Claisen–Cope rearrangement.
Total Synthesis of the Proposed Structure of Aldingenin B
作者:Michael T. Crimmins、Colin O. Hughes
DOI:10.1021/ol3007259
日期:2012.4.20
The first enantioselective total synthesis of the proposed structure of aldingenin B is reported in 16 steps from known compounds. The stereochemistry at C5 and C6 were established by an asymmetricacetalaldol. Following a ring-closing metathesis, a selective, substrate-controlled hydrogen bond-mediated dihydroxylation provided control of the C2 and C3 stereocenters. Discrepancies in the spectroscopic