The N-arylsulfonyl group, which is the best and most useful cyclization auxiliary for the transition-metal-catalyzed atom transfer radical cyclization (ATRC) of N-allyl-α-polychloroamides, can be effectively removed from the target γ-lactams by using H2SO4–HOAc, without impairing the halogen functions. The reaction involves H+ attack on the aromatic moiety, and is strongly responsive to the electronic properties of the substituent bound to the aromatic ring: electron-donating groups, such as methyl or methoxy are, in fact, required for efficient “deprotection”. The N-p-nitrophenylsulfonyl cyclization auxiliary, in contrast to all the other sulfonyl groups tested, proved to be unsuitable for the ATRC, owing to a side reductive transposition that halts the redox cycle.

Arylsulfonyl Groups: The Best Cyclization Auxiliaries for the Preparation of ATRC γ-Lactams can be Acidolytically Removed / Clark, A. J.; Cornia, Andrea; Felluga, F.; Gennaro, A.; Ghelfi, Franco; Isse, A. A.; Menziani, Maria Cristina; Muniz Miranda, F.; Roncaglia, Fabrizio; Spinelli, D.. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1099-0690. - STAMPA. - 2014:30(2014), pp. 6734-6745. [10.1002/ejoc.201402769]

Arylsulfonyl Groups: The Best Cyclization Auxiliaries for the Preparation of ATRC γ-Lactams can be Acidolytically Removed

CORNIA, Andrea;GHELFI, Franco;MENZIANI, Maria Cristina;F. Muniz Miranda;RONCAGLIA, Fabrizio;
2014-01-01

Abstract

The N-arylsulfonyl group, which is the best and most useful cyclization auxiliary for the transition-metal-catalyzed atom transfer radical cyclization (ATRC) of N-allyl-α-polychloroamides, can be effectively removed from the target γ-lactams by using H2SO4–HOAc, without impairing the halogen functions. The reaction involves H+ attack on the aromatic moiety, and is strongly responsive to the electronic properties of the substituent bound to the aromatic ring: electron-donating groups, such as methyl or methoxy are, in fact, required for efficient “deprotection”. The N-p-nitrophenylsulfonyl cyclization auxiliary, in contrast to all the other sulfonyl groups tested, proved to be unsuitable for the ATRC, owing to a side reductive transposition that halts the redox cycle.
2014
30
6734
6745
Arylsulfonyl Groups: The Best Cyclization Auxiliaries for the Preparation of ATRC γ-Lactams can be Acidolytically Removed / Clark, A. J.; Cornia, Andrea; Felluga, F.; Gennaro, A.; Ghelfi, Franco; Isse, A. A.; Menziani, Maria Cristina; Muniz Miranda, F.; Roncaglia, Fabrizio; Spinelli, D.. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1099-0690. - STAMPA. - 2014:30(2014), pp. 6734-6745. [10.1002/ejoc.201402769]
Clark, A. J.; Cornia, Andrea; Felluga, F.; Gennaro, A.; Ghelfi, Franco; Isse, A. A.; Menziani, Maria Cristina; Muniz Miranda, F.; Roncaglia, Fabrizio; Spinelli, D.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1047314
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