TY - JOUR
T1 - Two-directional elaboration of hydroxyacetone under thermodynamically controlled conditions
T2 - Allylation or 2-propynylation and aldol reaction
AU - Ishikawa, Teruhiko
AU - Aikawa, Toshiaki
AU - Ohata, Eiko
AU - Iseki, Takako
AU - Maeda, Satoshi
AU - Matsuo, Takashi
AU - Fujino, Tatsuo
AU - Saito, Seiki
PY - 2007/1/19
Y1 - 2007/1/19
N2 - Enolate generated from O-(tetrahydropyran-2-yl)hydroxyacetone under thermodynamically controlled conditions (1.3 equiv of NaH, THF, 0 °C to rt) was allylated at the carbon bearing the protected hydroxy group with very high regioselectively. When tert-BuOH, equivalent to the excessive portion of initially added NaH, was introduced into the mixture followed by addition of aldehyde, aldol reaction took place on the methyl group to give 1-substituted 4-hydroxy-(1E),6-heptadien-3-one in acceptable yields after acidic treatment of the mixture for dehydration and deprotection. Introducing a chiral auxiliary protecting group into hydroxyacetone led to asymmetric allylation though stereoselectivity was around 50% ee. Thus, the hidden aspect of the chemoselective nature of protected hydroxy acetone-derived enolate generated under thermodynamically controlled conditions has opened a new avenue for two-directional elaboration of hydroxyacetone that should be potentially useful in organic synthesis.
AB - Enolate generated from O-(tetrahydropyran-2-yl)hydroxyacetone under thermodynamically controlled conditions (1.3 equiv of NaH, THF, 0 °C to rt) was allylated at the carbon bearing the protected hydroxy group with very high regioselectively. When tert-BuOH, equivalent to the excessive portion of initially added NaH, was introduced into the mixture followed by addition of aldehyde, aldol reaction took place on the methyl group to give 1-substituted 4-hydroxy-(1E),6-heptadien-3-one in acceptable yields after acidic treatment of the mixture for dehydration and deprotection. Introducing a chiral auxiliary protecting group into hydroxyacetone led to asymmetric allylation though stereoselectivity was around 50% ee. Thus, the hidden aspect of the chemoselective nature of protected hydroxy acetone-derived enolate generated under thermodynamically controlled conditions has opened a new avenue for two-directional elaboration of hydroxyacetone that should be potentially useful in organic synthesis.
UR - http://www.scopus.com/inward/record.url?scp=33846217034&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846217034&partnerID=8YFLogxK
U2 - 10.1021/jo0618573
DO - 10.1021/jo0618573
M3 - Article
C2 - 17221959
AN - SCOPUS:33846217034
VL - 72
SP - 435
EP - 441
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 2
ER -