Active metabolites from natural sources are the predominant molecular targets in numerous biological studies owing to their appropriate compatibility with biological systems and desirable selective toxicities. Thus, their potential for therapeutic development could span a broad scope of disease areas, including pathological and neurological dysfunctions. Cardiac glycosides are a unique class of specialized metabolites that have been extensively applied as therapeutic agents for the treatment of numerous heart conditions, and more recently, they have also been explored as probable antitumor agents. They are a class of naturally derived compounds that bind to and inhibit Na+/K+-ATPase. This study presents cardiac glycosides and their analogues with highlights on their applications, challenges, and prospects as lead compounds for cancer treatment.

Phenoxazines have gained enormous interest because of their diverse applications in both material science and chemotherapy. They exhibit numerous biological activities, ranging from anti‐malarial, anticancer, antiviral, antidiabetic, anti‐Alzheimer, antioxidant, anti‐inflammatory, to antibiotic and many more. Actinomycin D, for instance, which embodies a phenoxazine scaffold, displays both antibiotic and anticancer property. Phenoxaxines have also found usefulness in organic light‐emitting diodes, fluorescent probes and dye‐sensitized solar cells. Over the years, various research groups have strived for several structural modifications targeting new derivatives of phenoxazines with improved properties. This present review highlights the progress, challenges and prospects in medicinal and material applications of phenoxazine moiety to provide greater insight into the development of future derivatives with improved properties.

Scheme 1. Diphenylprolinol silyl ether 1-mediated asymmetric conjugate additions. ChemCatChemCommunications

An asymmetric domino Michael/Michael reaction of α,β‐unsaturated aldehydes 1 and α‐acetyl‐β‐substituted‐α,β‐unsaturated esters 2 catalyzed by diphenylprolinol silyl ether was developed. This is a formal carbo [4+2] cycloaddition reaction affording penta‐substituted cyclohexanes having the three continuous chiral centers with excellent diastereo‐ and enantioselectivity.