Abstract:New pyrenyl substituted 9,9-diarylfluorene with nonplanar conformations, high fluorescence quantum yield and excellent thermal and morphological stability was synthesized by our current protocol.
“…2 and Table 2 , Supplementary Data 2 for CIF file). These products indeed offer high opportunity for further functionalization via a simple –OH group transformation 80 , 81 , and thus allows rich entities for new material investigations. Fig.…”
Existing synthetic routes for accessing dibenzofuran core have intrinsic regioselectivity, limiting the substitution patterns available in heteropolycyclic arene products. Here we report a double 1,4-conjugate addition/intramolecular annulation cascade reaction between propargylamines and two equivalents of imidazolium methylides that allows efficient access of structurally versatile dibenzofurans. This transition metal-free protocol proceeds smoothly under bench-top air atmosphere and offers easy manipulation of substituents on the dibenzofuran core, and also provides good-to-excellent product yields with good functional group tolerance, particularly the –Br and –Cl groups which are often incompatible with existing metal-catalyzed C–C and/or C–O bond ring-forming processes. It is worth noting that ladder-type π-systems with all-arene quarternary carbon structure can be straightforwardly generated upon simple late-stage functionalization.
“…2 and Table 2 , Supplementary Data 2 for CIF file). These products indeed offer high opportunity for further functionalization via a simple –OH group transformation 80 , 81 , and thus allows rich entities for new material investigations. Fig.…”
Existing synthetic routes for accessing dibenzofuran core have intrinsic regioselectivity, limiting the substitution patterns available in heteropolycyclic arene products. Here we report a double 1,4-conjugate addition/intramolecular annulation cascade reaction between propargylamines and two equivalents of imidazolium methylides that allows efficient access of structurally versatile dibenzofurans. This transition metal-free protocol proceeds smoothly under bench-top air atmosphere and offers easy manipulation of substituents on the dibenzofuran core, and also provides good-to-excellent product yields with good functional group tolerance, particularly the –Br and –Cl groups which are often incompatible with existing metal-catalyzed C–C and/or C–O bond ring-forming processes. It is worth noting that ladder-type π-systems with all-arene quarternary carbon structure can be straightforwardly generated upon simple late-stage functionalization.
A highly efficient HClO 4 catalysed substitutive phosphorylation of SO O-and N-based anthracene-9-ols with P(O)À H species has been developed to afford phosphorylated 9,10-dihydroanthracenes with a tetra-or trisubstituted carbon centre in good to excellent yields, which serves as a good complement to the established protocols that are limited to tertiary phosphorylated 9,10-dihydroanthracenes. Gram-scale synthesis and further elaboration highlight its synthetic utility.
A new efficient approach to highly substituted fluorenes has been presented by reacting 9-aryl-9-fluorenols with 1,1-diarylethylenes. These reactions were catalyzed by Sc(OTf) 3 and provided a wide variety of the corresponding products in excellent yields (up to 99 % yield). In addition, the initial photophysical property evaluation of certain products may inspire the development of potential OLEDs materials.
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