Download PDF
Synfacts 2014; 10(3): 0240
DOI: 10.1055/s-0033-1340806
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Spiroaminals and Spiroketals via Au/La and Au/Y Relay Catalysis

Contributor(s):
Victor Snieckus
,
Yigang Zhao (Snieckus Innovations)
Wang X, Dong S, Yao Z, Feng L, Daka P, Wang H, Xu Z * Shandong University, Jinan, P. R. of China and Miami University, Oxford, USA
Synthesis of Spiroaminals and Spiroketals with Bimetallic Relay Catalysis.

Org. Lett. 2014;
16: 22-25
Search in Google Scholar
Further Information

Publication History

Publication Date:
17 February 2014 (online)

 
 PDF Download Permissions and Reprints

Key words

spiroaminals - spiroketals - 2-alkynyl benzylamines - 2-alkynyl benzyl alcohols - gold catalysis

Significance

Reported is the synthesis of spiro­aminals 4 and -ketals 5 from the reaction of 2-alkynyl benzylamines 1 and benzyl alcohols 2 with keto esters 3 under mild Au/La or Au/Y catalytic conditions. Mechanisms involving gold-catalyzed cycloisomerization of 1 and 2 followed by a La- or Y-catalyzed hetero-Diels–Alder reaction were suggested. When an internal alkyne substrate 2 was employed, the fused bicyclic ketals 6a and 6b were formed possibly involving favored 6-endo-dig cyclization over the 5-exo-dig mode.


#

Comment

Spiroaminals and -ketals are important motifs often found in natural products and bioactive molecules which present broad-spectrum pharmaceutical activities, and a number of synthetic routes have been developed (see ­Reviews below). As a variation of the efficient palladium-catalyzed multicomponent reaction of 4-pentyn-1-ols, salicylaldehydes and amines or ­orthoesters for the construction of spiroketals (J. Barluenga, A. Mendoza, F. Rodríguez, F. J. ­Fañanás Angew. Chem. Int. Ed. 2009, 48, 1644), the current method is not only complementary for the synthesis of a new series of spiroketals, but also offers a new way to prepare spiroaminals.


#

Reviews

M.-E. Sinibaldi, I. Canet Eur. J. Org. Chem. 2008, 4391–4399; J. E. Aho, P. M. Pihko, T. K. Rissa Chem. Rev. 2005, 105, 4406–4440.


#
#


   Permissions and Reprints