TY - JOUR
T1 - Expanding the Scope of Primary Amine Catalysis
T2 - Stereoselective Synthesis of Indanedione-Fused 2,6-Disubstituted trans-Spirocyclohexanones
AU - Madhusudhan Reddy, G.
AU - Ko, Chi Ting
AU - Hsieh, Kai Hong
AU - Lee, Chia Jui
AU - Das, Utpal
AU - Lin, Wenwei
N1 - Funding Information:
The authors thank the Ministry of Science and Technology of the Republic of China (MOST 103-2113-M-003-009-MY3) for financial support.
PY - 2016/3/18
Y1 - 2016/3/18
N2 - A cinchona-alkaloid-derived chiral primary-amine-catalyzed enantioselective method for the synthesis of the thermodynamically less stable indanedione-fused 2,6-trans-disubstituted spirocyclohexanones is demonstrated. Both the enantiomeric forms of the trans isomer are obtained in excellent yields and enantioselectivities. Furthermore, one of the enantiopure trans-spiranes bearing an additional α-substitution on the cyclohexanone ring was then epimerized into its thermodynamically stable cis counterpart, with little loss of enantioselectivity to demonstrate the feasibility of such a transformation. Mechanistic investigations revealed two competing pathways, a concerted Diels-Alder reaction and a stepwise Michael addition, for the formation of corresponding products.
AB - A cinchona-alkaloid-derived chiral primary-amine-catalyzed enantioselective method for the synthesis of the thermodynamically less stable indanedione-fused 2,6-trans-disubstituted spirocyclohexanones is demonstrated. Both the enantiomeric forms of the trans isomer are obtained in excellent yields and enantioselectivities. Furthermore, one of the enantiopure trans-spiranes bearing an additional α-substitution on the cyclohexanone ring was then epimerized into its thermodynamically stable cis counterpart, with little loss of enantioselectivity to demonstrate the feasibility of such a transformation. Mechanistic investigations revealed two competing pathways, a concerted Diels-Alder reaction and a stepwise Michael addition, for the formation of corresponding products.
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U2 - 10.1021/acs.joc.5b02921
DO - 10.1021/acs.joc.5b02921
M3 - Article
AN - SCOPUS:84961615768
VL - 81
SP - 2420
EP - 2431
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 6
ER -