Enantio- and Diastereoselective 1,2-Additions to α-Ketoesters with Diborylmethane and Substituted 1,1-Diborylalkanes.
The catalytic enantioselective synthesis of boronate-substituted tertiary alcohols through additions of diborylmethane and substituted 1,1-diborylalkanes to α-ketoesters is reported. The reactions are catalyzed by readily available chiral phosphine/copper(I) complexes and produce β-hydroxyboronates containing up to two contiguous stereogenic centers in up to 99:1 e.r. and greater than 20:1 d.r. The utility of the organoboron products is demonstrated through several chemoselective functionalizations. Evidence indicates the reactions occur via an enantioenriched α-boryl-copper-alkyl intermediate.
Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
Stephanie A
SA
Murray
Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
Jacob C
JC
Green
Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
Sanita B
SB
Tailor
Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA. sjmeek@unc.edu.
Simon J
SJ
Meek
D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D000438:Alcohols; D000473:Alkanes; D001896:Boron Compounds; D004952:Esters; D007659:Ketones; D008697:Methane
asymmetric catalysis; boron; copper; enantioselectivity; reaction mechanisms