TY - JOUR
T1 - Diastereo- and enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine
T2 - Mechanistic insight into sequential nitroso aldol/Michael reaction and application for optically pure 1-amino-3,4-diol synthesis
AU - Momiyama, Norie
AU - Yamamoto, Yuhei
AU - Yamamoto, Hisashi
PY - 2007/2/7
Y1 - 2007/2/7
N2 - This article presents complete diastereo- and highly enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine. With the hydrogen bonding of two hydroxyls in the bulky binaphthol 1c, high enantioselectivities and complete diastereoselectivity are realized in 2-oxa-3-aza-bicycloketone synthesis. On the other hand, α,β- unsaturated ketone can be employed as diene precursor, utilizing readily available tetrazole catalyst 3b, to provide the 3-oxa-2-aza-bicycloketones in moderate yields with complete enantioselectivities. Investigation into the reaction utilizing 2-morpholino-4,4-diphenylcyclohexadiene 2d clearly indicated that cyclization with the bulky binaphthol 1c is involved in the sequential process, the N-nitroso aldol reaction, followed by Michael addition. In addition, optically pure 1-amino-3,4-diol is synthesized from 2-oxa-3-aza-bicycloketones. Use of p-phenoxynitrosobenzene allows access to protected amino diol via cleavage of the N-Ph bond.
AB - This article presents complete diastereo- and highly enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine. With the hydrogen bonding of two hydroxyls in the bulky binaphthol 1c, high enantioselectivities and complete diastereoselectivity are realized in 2-oxa-3-aza-bicycloketone synthesis. On the other hand, α,β- unsaturated ketone can be employed as diene precursor, utilizing readily available tetrazole catalyst 3b, to provide the 3-oxa-2-aza-bicycloketones in moderate yields with complete enantioselectivities. Investigation into the reaction utilizing 2-morpholino-4,4-diphenylcyclohexadiene 2d clearly indicated that cyclization with the bulky binaphthol 1c is involved in the sequential process, the N-nitroso aldol reaction, followed by Michael addition. In addition, optically pure 1-amino-3,4-diol is synthesized from 2-oxa-3-aza-bicycloketones. Use of p-phenoxynitrosobenzene allows access to protected amino diol via cleavage of the N-Ph bond.
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U2 - 10.1021/ja066037m
DO - 10.1021/ja066037m
M3 - Article
C2 - 17263400
AN - SCOPUS:33846781519
VL - 129
SP - 1190
EP - 1195
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 5
ER -