J. Am. Chem. SOC. 1995,117, 10417-10418
Preferential Hydrogenation of Aldehydes and Ketones
Table 1. Chemoselective Hydrogenation of Unsaturated Aldehydes and Ketones Catalyzed by a RUC~Z[P(C~H~)~]~-NH~(CHZ)~NH~-KOH System"
Takeshi Ohkuma, Hirohito Ooka, Takao Ikariya, and Ryoji Noyon**+
ERATO Molecular Catalysis Project Research Development Corporation of Japan 1247 Yachigusa, Yakusa-cho, Toyota 470-03, Japan Received June 12, 1995
10417
product distribution,
Hz,time, substrate solvent atm
la lb citral' 2
P/T P/T
4
P/T
4 4 4
P/T
4
h
% yieldb
0.3 0.5
(88)
0.3 2
unsatd satd satd alcohol alcohol ketone
100 99.7 (95) 99.8 (92) 100' 97.4 (95) 98.6 100 (97) 98.2 99.5 (98) 100 99.6 (96) 99.4 lOO(97) 299.9 98.2 (90) 99.6 100 70 99.8 (98) 299.9 lOO(95) 92% >99(96) 100
0 0 0
0
1.4
0
0.2 0
3 P/T 0.7 1.8 0 Complex metal hydrides are among the most widely used 4 P 4 1.5 0 0 reagents in organic synthesis.' NaBH4 is particularly appreci5 P 1 3 0 0.6 ated because of its high chemoselectivity for conversion of 5d P 4 18 0 99.9%, respectively. The solvent was removed under reduced pressure, and the residue was filtered through silica gel (100 g), eluted with a 2:8 mixture of ethyl acetate and hexane (1000 mL), and concentrated, giving (E)-4-phenyl-3buten-2-01 (29.4 g, 97% yield). Due to the instability of the allylic alcohol, direct distillation without silica gel treatment should be avoided.
