Catalytic enantioselective synthesis of tetrahydrofurans: a dynamic kinetic asymmetric [3 + 2] cycloaddition of racemic cyclopropanes and aldehydes.
A highly diastereoselective dynamic kinetic asymmetric transformation of racemic 1,1-cyclopropane diesters to prepare enantioenriched tetrahydrofuran (THF) derivatives has been developed. Asymmetric [3 + 2] cycloaddition of activated donor-acceptor (D-A) cyclopropanes and aldehydes catalyzed by ((t)Bu-pybox)MgI(2) gives THF products in good to excellent yields (48-92%) as single diastereomers with er's up to 97:3. Aryl, cinnamyl, and aliphatic aldehydes are competent dipolarophiles for this transformation.
Parsons
Andrew T
AT
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Johnson
Jeffrey S
JS
D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D003521:Cyclopropanes; D005663:Furans; D008024:Ligands; D009942:Organometallic Compounds