The carbo- and heterocyclic ring systems bearing cyclopropane are ubiquitous in many biologically active
natural products and in particular 3-azabicyclo[n.1.0]alkane framework is very common in many pharmaceutically
important drug molecules (Figure 1).1 As a result of their medicinal applications, several tedious multistep synthetic
approaches have been reported for the construction of 3-azabicyclo[n.1.0]alkane derivatives.2 In this context, for the first
time we have developed an one-pot synthesis of structurally complex cyclopropane-fused bicyclic amidine using CuBr2-
mediated oxidative cyclization of carbanion as a key strategy (Scheme 1).3 Moreover, silver oxide/ cupric bromide
catalyzed novel SET oxidative cyclization of α-amidinoester for the stereoselective synthesis of 3-
azabicyclo[n.1.0]alkanes has also been developed (Scheme 1).4
In this presentation, the synthetic utility of novel cyclic amidines such as a chemoselective reduction amidines to
3-azabicyclo[n.1.0]alkanes, preparation of 2-iminopyrrolidines, synthesis of iminosugar based (+/-)-epiquinamide
analogue, the concise synthesis of pharmaceutically important antidepressant drug candidate GSK13607073, and studies
towards the total synthesis of (+/-)-Cyclocavine, will be discussed (Scheme 1).
References:
1. (a) Donaldson, W. A. Tetrahedron 2001, 57, 8589. (b) Chen, D. Y.-K.; Pouwer, R. H.; Richard, J.-A. Chem. Soc. Rev.
2012, 41, 4631. (c) Kulinkovich, O. G. Cyclopropane In Organic Synthesis, Wiley, Hoboken, 2015, p. 432.
2. Ebner, C.; Carreira, E. M. Chem. Rev. 2017, 117, 11651.
3. Veeranna, K. D.; Das, K. K.; Baskaran, S. Angew. Chem., Int. Ed. 2017, 56, 16197.
4. Veeranna, K. D.; Das, K. K.; Baskaran, S. Chem. Commun., 2019, 55, 7647.