Practical and Broadly Applicable Catalytic Enantioselective Additions of Allyl-B(pin) Compounds to Ketones and α-Ketoesters.
A set of broadly applicable methods for efficient catalytic additions of easy-to-handle allyl-B(pin) (pin=pinacolato) compounds to ketones and acyclic α-ketoesters was developed. Accordingly, a large array of tertiary alcohols can be obtained in 60 to >98 % yield and up to 99:1 enantiomeric ratio. At the heart of this development is rational alteration of the structures of the small-molecule aminophenol-based catalysts. Notably, with ketones, increasing the size of a catalyst moiety (tBu to SiPh3 ) results in much higher enantioselectivity. With α-ketoesters, on the other hand, not only does the opposite hold true, since Me substitution leads to substantially higher enantioselectivity, but the sense of the selectivity is reversed as well.
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Daniel W
DW
Robbins
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
KyungA
K
Lee
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Daniel L
DL
Silverio
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Alexey
A
Volkov
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Sebastian
S
Torker
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Amir H
AH
Hoveyda
D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D000498:Allyl Compounds / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry*; D002074:Butanones / Q000737:chemistry*; D002384:Catalysis; D004952:Esters / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D000438:Alcohols; D000498:Allyl Compounds; D001896:Boron Compounds; D002074:Butanones; D004952:Esters; D007659:Ketones; C463639:bis(pinacolato)diboron
enantioselective synthesis; homoallylic alcohols; homogeneous catalysis; ketones; α-ketoesters