Heterocyclic Spiranes and Dispiranes via Enantioselective Phosphine‐Catalyzed [3+2] Annulations

Abstract

The synthesis of highly functionalized heterocyclic spiranes has been carried out by [3 + 2] cyclizations between allenoates and enones, under phosphine catalysis. Excellent enantioselectivity levels (ees up to 99%) have been attained in Ferro-PHANE-promoted cyclizations of this class, leading to chiral sulfides with unprecedented spiranic structures. The corresponding sulfoxides have been obtained then via a subsequent, highly diastereoselective oxidation of the prostereogenic sulfur centre.

Сhiral tricyclic phosphines derived from 1-(+)-neomenthyl-1,2-diphosphole: Synthesis and applications in asymmetric homogeneous catalysis

“…Thus, there was also excellent regioselectivity and enantioselectivity of this reaction for related rigid monocyclic [27][28][29] or bicyclic [12,18] monodentate chiral phosphines.…”

Phosphine Organocatalysis for the Synthesis of Spirocyclic Compounds

“…23 The enantioselective [3+2] cyclizations using these substrates would lead to highly functionalized heterocyclic spirane scaffolds. The potential of the targeted spirocycles can be anticipated, since analogous structures have found many applications in medicinal chemistry 24 and enantioselective synthesis.…”

Macozinone: revised synthesis and crystal structure of a promising new drug for treating drug-sensitive and drug-resistant tuberculosis

“…A search of the Cambridge Structural Database (CSD, Version 5.37; Groom et al, 2016) for the thiopyran-4-one fragment resulted in 42 hits, of which 10 possessing the most similar structures were compared with those of the title compound (Table S5 in the supporting information) (Narasimhamurthy et al, 2003;Duvvuru et al, 2012;Gendron et al, 2015;Rosiak et al, 2006;Schmidt et al, 2005;Ramalingam et al, 1979;Xu et al, 2015;Wang et al, 2011;Mojtahedi et al, 2011;Karisalmi et al, 2003). This is the first small-molecule crystal structure reported for macozinone or any BTZ analogue.…”