Enantioselective Synthesis of Cordiachromene

Abstract

An enantioselective synthesis of cordiachromene is described. An allylic alcohol moiety is first attached in the oposition to the methoxymethoxy substituent in 1-methoxy-4-methoxymethoxybenzene. Then chirality is introduced successively through asymmetric Sharpless epoxidation on the allylic alcohol moiety and regioselective ring-opening. The

Enantioselective 6-endo-trig Wacker-type cyclization of 2-geranylphenols: application to a facile synthesis of (−)-cordiachromene

“…24 The absolute configuration of the resulting 3a was assigned to be (R) by comparison of the sign of the specific rotation with the reported value. 15,16 This enantioselective 6-endo-trig cyclization of 1 seems to proceed through a general catalytic cycle of Wacker-type reaction, that is, an initial coordination of the olefin to Pd(II), a subsequent intramolecular attack of the nucleophile, and a final b-hydride elimination producing chromenes 3. From the results shown in Table 1, the use of ligand 4 is essential for promoting this cyclization.…”

Stereoselective Reductive Opening of 2,3-Benzofuran − A Two-Step Synthesis of 2H-Chromenes Including Deoxycordiachromene

“…In the last part of this study we report the application of the methodology shown above to the two‐step synthesis of deoxycordiachromene ( 4j ) 15. Thus, once the ring opening of 2,3‐benzofuran ( 1 ) took place as described above, the intermediate 2 was allowed to react with commercially available 6‐methyl‐5‐hepten‐2‐one under the same reaction conditions as for compounds 3 , giving the expected product 3j (45% isolated yield after column chromatography).…”

Chemoselective Transformations of Aromatic Methoxymethyl Ethers Using Trialkylsilyl Triflate and 2,2′-Bipyridyl

“…The residue was purified by column chromatography on a silica gel to give a MOM ether 1 . 1a , 9 1b , 10 1c , 11 1d , 12 1e , 13 1f , 14 1h , 15 and 4 (16) are known compounds.…”