General Asymmetric Synthetic Strategy for the α‐Alkylated 2,5,6‐Trisubstituted Pyran of Indanomycin and Related Natural Products

Abstract

A general synthetic strategy for convergent asymmetric synthesis of C1–C10 fragment of tetraene‐containing natural product indanomycin was achieved starting from 2‐(benzyloxy)acetaldehyde which in turn was obtained from very inexpensive material cis‐1,4‐butene‐diol. Key steps include Evans' aldol reaction, HWE olefination, iodine‐catalyzed tandem isomerization followed by C–O and C–C bond formation similar to our earlier report in constructing the trans‐2,6‐disubstituted dihydropyran ring and Evans' asymmetric alkylation.