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Chiral Allyl Cations Are Captured by Furan with 100 % Stereoselectivity: Synthesis of Enantiopure 2‐Alkoxy‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐ones by Low‐Temperature [4+3] Cycloaddition
Author(s) -
Stark Christian B. W.,
Pierau Sabine,
Wartchow Rudolf,
Hoffmann H. M. R.
Publication year - 2000
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/(sici)1521-3765(20000218)6:4<684::aid-chem684>3.0.co;2-z
Subject(s) - enantiopure drug , furan , stereocenter , stereoselectivity , cycloaddition , chemistry , dichloromethane , yield (engineering) , alkoxy group , enantiomer , dilution , intermolecular force , medicinal chemistry , organic chemistry , stereochemistry , enantioselective synthesis , catalysis , materials science , molecule , physics , alkyl , solvent , metallurgy , thermodynamics
A low‐temperature (−95 °C) protocol for intermolecular cycloadditions of furan to chiral silyloxyallyl cations in dichloromethane is described. Key precursors are open‐chain, mixed α ‐ketoacetals, which are chiral. The resulting [4+3] cycloadducts are densely functionalized and are isolated as single enantiomers in high chemical yield. The yield of the cycloadducts increases with increasing dilution. Three and four stereogenic centres are created in one single step.