Oxidative Coupling Reactions of 1,3‐Diarylpropene Derivatives to Dibenzo[a,c]cycloheptenes by PIFA

Abstract

The oxidative cyclization reactions of a variety of α-benzylcinnamates can be selectively performed with hypervalent iodine as an oxidant. The dibenzo[a,c]cycloheptenes were isolated in up to 55 % yield. When an oxo substrate is applied, the yield was significantly increased. With this syn-

MoV Reagents in Organic Synthesis

“…The introduction of various fragments on the seven‐membered ring system (see the blue fragment in 46 , Scheme ) was only possible by MoCl 5 in the presence of TiCl 4 . Other reagent systems such as FeCl 3 did not lead to the desired products 11b…”

“…Use of MoCl 5 in the absence of TiCl 4 leads to the formation of the dimeric product 47 . With PIFA only the aryl‐aryl bond is constructed (compounds 48 , Scheme ) 11b…”

Metal‐Free Oxidative CC Bond Formation through CH Bond Functionalization

“…However, the use of unsaturated tethers has since been successfully demonstrated ( 2 e – g ; Scheme ). Waldvogel and co‐workers reported a similar PhI(CO 2 CF 3 ) 2 ‐mediated oxidative cyclization of α‐benzylcinnamic acid derivatives to the tricyclic compounds 2 e , which represents an important skeletal motif found in many biologically active compounds such as allocolchicine 13. According to the authors, other common oxidants, like FeCl 3 and 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), failed to initiate the required cyclization, whereas MoCl 5 led to over‐oxidation of the product.…”

Chemical approaches to inhibitors of isoprenoid biosynthesis: targeting farnesyl and geranylgeranyl pyrophosphate synthases

“…132 In addition, the insertion of carboxylic function can be performed by using lithium alkylphosphonate and diethyl carbonate 133 or CO 2 . 134 Another methods include alkylation of trialkyl phosphonoacetate 135 and functionalization of trialkyl 2-phosphonoacrylate via Michael-type addition. 136 Recently, Coxon and colleagues used various approaches among those described to synthesize phosphonocarboxylates 175-178 showing some structural diversity (Fig.…”