Application of Ugi/De-Boc/Cyclization Strategy in the Synthesis of Nitrogen-Containing Heterocycles

Abstract

Ugi/de-Boc/cyclization (UDC) strategy represents a "three-step, one-pot procedure", employing the Ugi multicomponent reaction utilizing one bi-functional group substrates with N-Boc-protected amino, followed by Boc-deprotection and cyclization to synthesize nitrogen-containing heterocycles. This strategy has the characteristics of rapid, efficiency, economy and structural diversity, which can be used to build libraries of complex nitrogen-containing heterocycles and has drawn much attention recently. In this paper, the research progress of UDC strategy in the synthesis of five-, six-and seven-membered heterocycles and natural products were summarized.

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

“…Dömling and co-workers, 2003 [37] (1 equiv) Ti(OiPr) 4 (1.35 equiv) THF (0.5 M), overnight 12-48 [32][33][34][35][36][37][38][39][40][41][42] Schreiber and co-workers, 2004 [38] (20 mol %) Cu(OTf) 2 ( [23,24] reactions that rely on the ability of organic isocyanides to participate in the nucleophilic attack onto the carbonyl or imine group are among the most studied MCRs. Accordingly, a wide range of post-MCR transformations have been elaborated allowing to upgrade the Passerini and Ugi adducts into potentially bioactive heterocycles [25][26][27][28][29][30][31][32]. While both Passerini and Ugi reactions proved to be quite robust towards different classes of substrates and possess broad functional group tolerance, the difficulties associated with controlling their stereochemical outcome [33][34][35] severely restrict their applicability in medicinal chemistry [36].…”