K-252c

The Michael addition of the carbanions derived from esters to nitroalkenes followed by reductive cyclization has been used extensively for the preparation of pyrrolidin-2-ones (Eq. 10.76).124 This strategy is used for synthesis of the carbazole alkaloid staurosporine aglycon (K-252c).124c... 

From Figure 7 one may infer that aglycon 2 is itself a natural product, commonly referred to as staurosporinone or K-252c. Because it constitutes a major unit of many indolocarbazole natural products, several approaches to its S3mthesis have been developed [31-32]. Classified by the last covalent bond(s) formed, these approaches include cycloaromatization (A), double nitrene C-H insertion (B, B ), nitrene C-H insertion (B ), maleimide reduction (C), and diazolactam initiated cycloaromatization (D). 

Synthesis ofpyrrolidin-2-ones and staurosporine aglycon (K-252c) by intermolecular Michael reaction... 

McCombie SW, Bishop RW, Carr D, Dobek E, Kirkup MP, Kirschmeir P, Lin SI, Pet-rin J, Rosinski K, Shankar BB, Wilson O. Indolocarbazoles. 1. Total s)mthesis and protein kinase inhibiting characteristics of compounds related to K-252c. Biooig. Med. Chem. Lett. 1993 3 1537-1542. 

Mahboobi S, Eibler E, Roller M, Kumar KCS, Popp A. S)mthesis of p3rrrohdin-2-ones and of staurosporine aglycon (K-252c) by intermolecular Michael reaction. J. Oig. Chem. 1999 64 4697- 4704. 

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