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.
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Li
L
Qiu
Quan
Q
Wang
Li
L
Lin
Xiaodong
X
Liu
Xianxing
X
Jiang
Qingyang
Q
Zhao
Guowen
G
Hu
Rui
R
Wang
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