TY - JOUR
T1 - Zr(OBut)4 as an effective promoter for the Meerwein-Ponndorf-Verley alkynylation and cyanation of aldehydes
T2 - Development of new asymmetric cyanohydrin synthesis
AU - Ooi, Takashi
AU - Miura, Tomoya
AU - Takaya, Keisuke
AU - Ichikawa, Hayato
AU - Maruoka, Keiji
PY - 2001/1/28
Y1 - 2001/1/28
N2 - Zr(OBut)4 can serve as an effective promoter for the Meerwein-Ponndorf-Verley alkynylation of aldehydes and also facilitate MPV type cyanide transfer to aldehyde carbonyls with commercially available acetone cyanohydrin under mild conditions. Based on this finding, a new procedure for asymmetric cyanohydrin synthesis has been developed employing (4R,5R)-2,2-dimethyl-α,α,α′,α′-tetraph enyl-1,3-dioxolane-4,5-dimethanol (TADDOL, 6) as a chiral ligand. For instance, sequential treatment of CH2Cl2 solution of 6 (1 equiv.) with Zr(OBut)4 (1 equiv.) and acetone cyanohydrin (2 equiv.) at room temperature for 1 h, and subsequent reaction with 3-phenylpropanal at -40°C for 7.5 h resulted in formation of the corresponding cyanohydrin 5g [R=Ph(CH2)2] in 63% isolated yield with 85% ee. The scope and limitations of this method have been clarified with various aldehydes as substrates.
AB - Zr(OBut)4 can serve as an effective promoter for the Meerwein-Ponndorf-Verley alkynylation of aldehydes and also facilitate MPV type cyanide transfer to aldehyde carbonyls with commercially available acetone cyanohydrin under mild conditions. Based on this finding, a new procedure for asymmetric cyanohydrin synthesis has been developed employing (4R,5R)-2,2-dimethyl-α,α,α′,α′-tetraph enyl-1,3-dioxolane-4,5-dimethanol (TADDOL, 6) as a chiral ligand. For instance, sequential treatment of CH2Cl2 solution of 6 (1 equiv.) with Zr(OBut)4 (1 equiv.) and acetone cyanohydrin (2 equiv.) at room temperature for 1 h, and subsequent reaction with 3-phenylpropanal at -40°C for 7.5 h resulted in formation of the corresponding cyanohydrin 5g [R=Ph(CH2)2] in 63% isolated yield with 85% ee. The scope and limitations of this method have been clarified with various aldehydes as substrates.
KW - Alkynylation
KW - Cyanation
KW - Cyanohydrin
UR - http://www.scopus.com/inward/record.url?scp=0035961110&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035961110&partnerID=8YFLogxK
U2 - 10.1016/S0040-4020(00)01040-1
DO - 10.1016/S0040-4020(00)01040-1
M3 - Article
AN - SCOPUS:0035961110
VL - 57
SP - 867
EP - 873
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 5
ER -