545375-01-7

Upstream product

• 70887-29-5 4-methoxybenzyl iodide 
• 545374-99-0 (1R,4aR,8aS)-cis-5-(4-methoxy-benzyloxymethyl)-8a-methyl-1,4,4a,8a-tetrahydronaphthalen-1-ol 
• 545374-98-9 (5S,6R)-5-acetyl-6-(2-ethoxyethenyl)-5-methylcyclohexa-1,3-diene-1-carboxaldehyde 
• 545375-33-5 (1R,4aR,8aS)-cis-5-hydroxymethyl-8a-methyl-1,4,4a,8a-tetrahydronaphthalen-1-ol 
• 862207-42-9 (4aS,8aR)-cis-4a-methyl-5-oxo-4a,5,8,8a-tetrahydro-naphthalene-1-carbaldehyde 

Downstream Products

• 545374-90-1 (3aS,4aS,8aS,9aS)-cis-5-(4-methoxy-benzyloxymethyl)-3,8a-dimethyl-3a,4,4a,8a,9,9a-hexahydro-3H-naphtho[2,3-b]furan-2-one 

Relevant academic research and scientific papers

Chromium-mediated dearomatization: Application to the synthesis of racemic 15-acetoxytubipofuran and asymmetric synthesis of both enantiomers

An efficient dearomatization process of [Cr(arene)(CO)3] complexes initiated by a nucleophilic acetaldehyde equivalent is detailed. It generates in a one-pot reaction three C-C bonds and two stereogenic centers. This process allowed a rapid assembly of a cis-decalin ring system incorporating a homoannular diene unit in just two steps starting from aromatic precursors (Scheme 2). The method was applied to the total synthesis of the eudesmane-type marine furanosesquiterpene (±)-15-acetoxytubipofuran (2). Two routes were successfully used to synthesize the γ-lactone precursor of the furan ring. The key step in the first approach was a Pd-catalyzed allylic substitution (Scheme 3), while in the second approach, an Eschenmoser-Claisen rearrangement was highly successful (Scheme 4). The Pd-catalyzed allylic substitution could be directed to give either the (normal) product with overall retention as major diastereoisomer or the unusual product with inversion of configuration (see Table). For the synthesis of the (-)-enantiomer (R,R)-2 of 15- acetoxytubipofuran, an enantioselective dearomatization in the presence of a chiral diether ligand was implemented (Scheme 7), while the (+)-enantiomer (S,S)-2 was obtained via a diastereoselective dearomatization of an arene-bound chiral imine auxiliary (Scheme 8). Chiroptical data suggest that a revision of the previously assigned absolute configuration of the natural product is required.

Chromium-mediated asymmetric synthesis of both enantiomers of acetoxytubipofuran

Both enantiomers of acetoxytubipofuran were synthesized using enantioselective and diastereoselective dearomatization sequences starting from the benzaldehyde chromium tricarbonyl complex. Following aldol condensation, a sequence involving Pd-catalyzed allylic substitution was used in the synthesis of the (-)-enantiomer, whereas the (+)-enantiomer was reached via an Eschenmoser-Claisen rearrangement. Chiroptical data show that a revision of the previously assigned absolute configuration of the natural product is required. Copyright