Phosphine-mediated Highly Enantioselective Spirocyclization with Ketimines as Substrates.
Angew Chem Int Ed Engl
; 55(22): 6492-6, 2016 05 23.
Article
em En
| MEDLINE
| ID: mdl-27080309
ABSTRACT
Phosphine-catalyzed enantioselective annulation reactions involving ketimines are a daunting synthetic challenge owing to the intrinsic low reactivity of ketimine substrates. A highly enantioselective [3+2] cycloaddition reaction that makes use of isatin-derived ketimines as reaction partners was developed. Notably, both simple and γ-substituted allenoates could be utilized, and various 3,2'-pyrrolidinyl spirooxindoles with a tetrasubstituted stereocenter were obtained in excellent yields and with nearly perfect enantioselectivity (>98 % ee in all cases).
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MEDLINE
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En
Ano de publicação:
2016
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Article