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Bifunctional Hydrogen‐Bond Donors That Bear a Quinazoline or Benzothiadiazine Skeleton for Asymmetric Organocatalysis
Author(s) -
Inokuma Tsubasa,
Furukawa Masaya,
Uno Takuya,
Suzuki Yusuke,
Yoshida Kohzo,
Yano Yoshiaki,
Matsuzaki Katsumi,
Takemoto Yoshiji
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201101338
Subject(s) - chemistry , enantioselective synthesis , catalysis , cycloaddition , thiourea , isomerization , pyrrolidine , organocatalysis , bifunctional , medicinal chemistry , combinatorial chemistry , organic chemistry , benzothiadiazine
Hydrogen‐bond (HB)‐donor catalysts that bear a 2‐aminoquinazolin‐4‐(1 H )‐one or a 3‐aminobenzothiadiazine‐1,1‐dioxide skeleton have been developed, and it has been shown that these catalyst motifs act similarly to other HB‐donor catalysts such as thioureas. The highly enantioselective hydrazination of 1,3‐dicarbonyl compounds was realized even at room temperature with up to 96 % ee for 2‐aminoquinazolin‐4‐(1 H )‐one‐type catalysts, which were more effective than the corresponding urea and thiourea catalysts. In addition, benzothiadiazine‐1,1‐dioxide‐type catalysts were shown to promote the isomerization of alkynoates to allenoates with high enantioselectivity. To overcome the problem that the products were obtained as mixtures with the starting alkynoates, we developed the tandem isomerization and cycloaddition of alkynoates for the synthesis of advanced chiral compounds such as bicyclo[2.2.1]heptenes and 3‐alkylidene pyrrolidine without a significant loss of enantioselectivity.