A 14-membered macrocycle with an allene and a furan strategically located at across the ring from each other is synthesized using an allene ring closing metathesis reaction. Upon treatment of the macrocycle with a catalytic amount of Pd(OAc)(2) and other additives, the first transannular [4+3] cycloaddition occurred to yield 37% of a tetracyclic compound containing the ABC ring structure of the...

A novel three-component reaction has been developed to assemble biologically and pharmaceutically important tetracyclic fused imidazo[1,2-a]pyridines in a one-pot fashion utilizing readily available 2-aminopyridines, isatins and isocyanides. The three-component coupling proceeds through the Groebke-Blackburn-Bienaymé reaction followed by a retro-aza-ene reaction and subsequent nucleophilic reac...

The first total synthesis of mycoleptodiscin A, a structurally unusual indolosesquiterpenoid possessing an ortho-benzoquinone motif, has been accomplished. A sulfone alkylation coupled two readily available fragments to give an aryl triene intermediate. The tetracyclic core of the molecule was assembled through a highly enantioselective iridium-catalyzed polyene cyclization. The benzylic homolo...

Here, we describe a new and simple synthetic strategy to various polycyclic sulfones via Diels-Alder reaction and ring-rearrangement metathesis (RRM) as the key steps. This approach delivers tri- and tetracyclic sulfones with six (n = 1), seven (n = 2) or eight-membered (n = 3) fused-ring systems containing trans-ring junctions unlike the conventional all cis-ring junctions generally obtained d...

Three triterpenes having the 6/6/5-fused tri- and 6/6/6/5-fused tetracyclic skeletons were isolated from an incubation mixture of the mutated F601A enzyme, these products being in accordance with a Markovnikov closure. Successful trapping of the tricyclic cationic intermediate by using the squalene analog having a highly nucleophilic hydroxyl group leads us to propose that the ring expansion pr...

dl-2-(7,11-Dimethyl-3,7,11 - trans,trans-dodecatrienyl)-3-methyl-cyclopent-2-enol was prepared by reduction of the corresponding ketone. This tetraenol, on treatment with trifluoroacetic acid, underwent stereoselective cyclization to give dl-3,17-dimethyl-A-nor-D-homoestra-3,16-diene. This tetracyclic material was readily converted, by oxidative cleavage to the bicyclic triketo aldehyde followe...

the order graph of a group $g$, denoted by $gamma^*(g)$, is a graph whose vertices are subgroups of $g$ and two distinct vertices $h$ and $k$ are adjacent if and only if $|h|big{|}|k|$ or $|k|big{|}|h|$. in this paper, we study the connectivity and diameter of this  graph. also we give a relation between the order graph and prime  graph of a group.

let f, g and h be non-empty graphs. the notation f → (g,h) means that if any edge of f is colored by red or blue, then either the red subgraph of f con- tains a graph g or the blue subgraph of f contains a graph h. a graph f (without isolated vertices) is called a ramsey (g,h)−minimal if f → (g,h) and for every e ∈ e(f), (f − e) 9 (g,h). the set of all ramsey (g,h)−minimal graphs is denoted by ...