Copper(I) complexes of fesulphos ligands: Highly efficient chiral lewis acids for the formal Aza Diels-Alder reaction of N-sulfonyl imines

Full text of DOI:10.1080/10426500590913483

This article was downloaded by: [University of Sherbrooke]
On: 07 November 2014, At: 07:28
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
Copper(I) Complexes of
Fesulphos Ligands: Highly
Efficient Chiral Lewis Acids
for the Formal Aza Diels–Alder
Reaction of N-Sulfonyl Imines
Juan C. Carretero a , Olga García Mancheño a
Ramón Gómez Arrayás a
&
a Departamento de Química Orgánica, Universidad
Autónoma de Madrid , Madrid, Spain
Published online: 16 Aug 2006.
To cite this article: Juan C. Carretero , Olga García Mancheño & Ramón Gómez
Arrayás (2005) Copper(I) Complexes of Fesulphos Ligands: Highly Efficient
Chiral Lewis Acids for the Formal Aza Diels–Alder Reaction of N-Sulfonyl Imines,
Phosphorus, Sulfur, and Silicon and the Related Elements, 180:5-6, 1515-1516, DOI:
10.1080/10426500590913483
To link to this article: http://dx.doi.org/10.1080/10426500590913483
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,
or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with

primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or
indirectly in connection with, in relation to or arising out of the use of the
Content.
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 180:1515–1516, 2005
Copyright © Taylor & Francis Inc.
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500590913483
Copper(I) Complexes of Fesulphos Ligands: Highly
Efficient Chiral Lewis Acids for the Formal Aza
Diels–Alder Reaction of N-Sulfonyl Imines
´
˜
´
Olga Garcıa Mancheno
´
´
Ramon Gomez Arrayas
Juan C. Carretero
Departamento de Qu´ımica Orga´nica, Universidad Auto´noma de Madrid,
Madrid, Spain
Keywords Aza Diels-Alder; copper-catalyzed; N-sulfonyl imines; planar chirality; sulfur
ligand
INTRODUCTION
Enantiopure dihydropyridones are intermediates of great interest
in alkaloid synthesis.1 The enantioselective Aza Diels–Alder re-
action (ADAR) of electron-rich dienes with aldimines is one of
the most powerful strategies for the construction of such nitrogen
heterocycles.
Herein we describe how copper(I) complexes of planar chiral
Fesulphos ligands2 act as highly efficient catalysts in enantioselec-
tive ADAR of N-sulfonyl imines with Danishefsky diene.3 The ap-
plication of this methodology to the synthesis of alkaloids is also
presented.
SCHEME 1 Enantioselective Aza Diels–Alder reaction of N-sulfonyl imines.
Received July 9, 2004; accepted October 5, 2004.
Address correspondence to Juan C. Carretero, Departamento de Qu´ımica Orga´nica,
Universidad Auto´noma de Madrid, Cantoblanco, 28049 Madrid, Spain. E-mail:
juancarlos.carretero@uam.es
1515

1516
O. G. Manchen˜o et al.
TABLE I Scope of the ADAR in the Presence
of Fesulphos-Copper Catalyst
R1
R2
ee (%)a
2-Thiophen
(p-NO2)C6H4
(p-OMe)C8H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
(p-Me)C6H4
Ph
Ph
Ph
Ph
93b
90b
94b
93b(97)c
88b(93)c
91b
(p-F)C6H4
(p-OMe)C6H4
2-Naph
PhCH CH
n-Pr
86b(93)c
83b(96)c
82b
aDetermined by HPLC. bAt rt. cAt −20◦C. dAt −78◦C.
RESULTS
High enantioselectivities (ee = 82–97%, in CH2Cl2) were achieved with
a number of N-aryl sulfonyl imines derived from both aliphatic and
aromatic aldehydes (Scheme 1 and Table I). Interestingly, the enan-
tioselectivity is high, regardless of the substitution at the arylsulfonyl
group.
Ready access to (2R, 4S, 6R)-4-hydroxy-2-phenyl-6-methylpip-
eridine4 from the phenyl cycloadduct (R2 = Ph), which was obtained
in enantiopure form upon a single recrystallization, has been accom-
plished by simple functional group transformations (Scheme 2).
SCHEME 2 Synthesis of (2R, 4S, 6R)-4-hydroxy-2-phenyl-6-methylpiperidine.
REFERENCES
[1] D. O’Hagan, Nat. Prod. Rep., 17, 435 (2000); D. L. Comins, S. Huang, C. L. McArdle,
and C. L. Ingalls, Org. Lett., 3, 469 (2001) and references cited therein.
[2] O. Garc´ıa Manchen˜o, J. Priego, S. Cabrera, R. Go´mez Arraya´s, T. Llamas, and J. C.
Carretero, J. Org. Chem., 68, 3679 (2003).
[3] For a previous communication, see O. Garc´ıa Manchen˜o, R. Go´mez Arraya´s, and
J. C. Carretero, J. Am. Chem. Soc., 126, 456 (2004).
[4] F. A. Davis, A. Rao, and P. J. Caroll, Org. Lett., 5, 3855 (2003), and references cited
therein.