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Asymmetric Total Synthesis of Nigerone and ent ‐Nigerone: Enantioselective Oxidative Biaryl Coupling of Highly Hindered Naphthols
Author(s) -
Kozlowski Marisa C.,
Dugan Elizabeth C.,
DiVirgilio Evan S.,
Maksimenka Katja,
Bringmann Gerhard
Publication year - 2007
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200600570
Subject(s) - chemistry , enantioselective synthesis , oxidative coupling of methane , natural product , enantiomer , isomerization , circular dichroism , stereochemistry , combinatorial chemistry , coupling (piping) , organic chemistry , catalysis , mechanical engineering , engineering
An enantioselective synthesis of the chiral bisnaphthopyrone natural product nigerone and its enantiomer, ent ‐nigerone, has been realized. The use of constrained 2‐naphthol substrates was critical to producing highly functionalized chiral 1,1′‐binaphthols via asymmetric oxidative biaryl coupling with 1,5‐diaza‐ cis ‐decalin copper complexes. The final natural product was formed via a key eight‐step isomerization process of the coupling product, bisisonigerone, and proceeded with retention of the biaryl configuration. The axial configurations of bisisonigerone and nigerone were definitively established by a combination of circular dichroism (CD) measurements and quantum chemical CD calculations.