A synthesis of iodo-substituted dibenzocyclohepten-5-ones by the iodine monochloride (or iodine)-induced intramolecular 7-endo-dig cyclization of 1-([1,1'-biphenyl]-2-yl)alkynones is reported. Detailed investigations on the substituent effects during the electrophilic iodocyclization of the alkynones show that they play a crucial role in determining the reaction pathways of the cyclization. By modifying the substitution pattern on the alkynone substrates, the cyclization takes place regioselectively, leading to either dibenzocyclohepten-5-ones, via a 7-endo-dig cyclization, or spiroconjugated compounds, via a 6-endo-dig cyclization.

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Tightly-regulated levels of retinoic acid (RA) are critical for promoting normal vertebrate development. The extensive history of research on RA has shown that its proper regulation is essential for cardiac progenitor specification and organogenesis. Here, we discuss the roles of RA signaling and its establishment of networks that drive both early and later steps of normal vertebrate heart development. We focus on studies that highlight the drastic effects alternative levels of RA have on early cardiomyocyte (CM) specification and cardiac chamber morphogenesis, consequences of improper RA synthesis and degradation, and known effectors downstream of RA. We conclude with the implications of these findings to our understanding of cardiac regeneration and the etiologies of congenital heart defects.

Herein, we report the [Bis(trifluoroacetoxy)iodo]benzene mediated C−H bond arylselenylation of 4H‐Pyrido‐[1,2‐a]‐Pyrimidin‐4‐ones using readily available organodiselenides. This methodology is scalable and permits for the generation of a broad spectrum of functionally and structurally diverse selenoether derivatives in very promising yields (up to 98%). Notably, this protocol proceeds at ambient conditions and in the absence of a metal. The application of this methodology for the facile synthesis of ArSe substituted 5H‐thiazolo‐pyrido[3,2‐a]pyrimidin‐4‐ones is also demonstrated.

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Synthesis of Dibenzocyclohepten-5-ones by Electrophilic Iodocyclization of 1-([1,1'-Biphenyl]-2-yl)alkynones. -A facile method to prepare dibenzocyclohepten-5-ones, the core structure of allocolchicine, is reported. The nature of substituents in distal phenyl ring is found to play an important role on the reaction outcome. For example, strongly electron-donating groups at para position favor formation of undesired spiroconjugated compounds via 6-endo-dig cyclization, while the 3,4,5-trimethoxyphenyl predominates 7-endo-dig cyclization to dibenzocycloheptenones. -(CHEN*, Y.; HUANG, C.; LIU, X.; PERL, E.; CHEN, Z.; NAMGUNG, J.; SUBRAMANIAM, G.; ZHANG, G.; HERSH, W. H.; J. Org. Chem. 79 (2014) 8, 3452-3464, http://dx.