Highly enantioselective addition of terminal alkynes to aldehydes catalyzed by a new chiral beta-sulfonamide alcohol/Ti(OiPr)4/Et2Zn/R3N catalyst system.
A new catalytic system, generated from the readily available and inexpensive beta-sulfonamide alcohol L*, Ti(O(i)Pr)(4), Et(2)Zn, and tertiary amine base (R(3)N), effectively catalyzes the enantioselective addition of various terminal alkynes including some quite challenging alkynes to aldehydes in good yields and excellent enantioselectivities. Up to 96% yield and >99% enantioselectivity were achieved with the use of N,N-diisoproylethylamine (DIPEA) as an additive in this asymmetric addition.
Qiu
Li
L
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Wang
Quan
Q
Lin
Li
L
Liu
Xiaodong
X
Jiang
Xianxing
X
Zhao
Qingyang
Q
Hu
Guowen
G
Wang
Rui
R
D000447:Aldehydes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D009942:Organometallic Compounds / Q000737:chemistry*; D000439:Pentanols / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013449:Sulfonamides / Q000737:chemistry*; D014105:Tosyl Compounds / Q000737:chemistry*
D000447:Aldehydes; D000480:Alkynes; D000588:Amines; D009942:Organometallic Compounds; D000439:Pentanols; D013449:Sulfonamides; D014105:Tosyl Compounds; C102815:titanium isopropoxide; C454811:diethylzinc