Highly enantioselective vinyl additions of vinylaluminum to ketones catalyzed by a titanium(IV) catalyst of (S)-BINOL.
We report a novel asymmetric addition of vinyl group to ketones using vinylaluminum reagents catalyzed by in situ prepared Ti(O(i)Pr)(4) complexes of (S)-BINOL to afford diversified tertiary allylic alochols. Varieties of aromatic ketones bearing either an electron-donating or an electron-withdrawing substituent on the aromatic ring were examined to afford products in excellent enantioselectivities of up to 98% ee with high yields. A 10-fold scale-up reaction afforded the product in a similar yield with a comparable enantioselectivity. More importantly, additions of a variety of vinyl reagents including functionalized vinyls were demonstrated, affording tertiary allylic alcohols with good to excellent enantioselectivities of up to 96% ee.
Biradar
Deepak Baburao
DB
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
Gau
Han-Mou
HM
D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry; D000535:Aluminum / Q000737:chemistry; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D014025:Titanium / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
D000480:Alkynes; C406944:BINOL, naphthol; D007659:Ketones; D009284:Naphthols; D009942:Organometallic Compounds; D014753:Vinyl Compounds; D000535:Aluminum; D014025:Titanium