2- benzofuran, synthesis

Thieno[3,4-6]benzofuran, aryl-reduction, 4, 1074 Thieno[3,4-6]benzofurans synthesis, 4, 1074 Thienobenzo thiophenes synthesis, 4, 758... 

RAPP - STOERMER Ban20furansynthesis Benzofuran synthesis from sallcylaldehydes and a-haioketones... 

K. Gewald and H. J. Jiinsch, J. Prakt. Chem. 315, 779 (1973). (novel general synthesis of 3-aininobenzofurans Gewakl s benzofuran synthesis, extended Rap method to o-cyanophenols). 

Benzofuran synthesis from salicylaldehydes and a-haloketones (see 1st edition). 

The Heck intramolecular reaction can be applied to many other heterocycles in Scheme 4.38, a benzofuran synthesis is shown. ... 

Other parameters of the palladium(n)-catalysed benzofuran synthesis were explored. Ultimately, it was found that the ideal system employed a 2 1 ligand/palladium ratio (10mol% Pd(OAc)2 and 20mol% ethyl nicotinate) and a substoichiometric amount (20mol%) of NaOAc at 100 °C. With this system in hand, a variety of substituted benzo-furans were accessed (Figure 9.7). The reaction was limited to electron-rich aryl systems the palladation event required a sufficiently nucleophilic arene in order to occur. The aryl subunit, however, tolerated an array of alkyl and alkoxy substitution patterns within the... 

The mechanistic rationale for the dramatic Lewis acid effect on the course of the Engler indole/benzofuran synthesis involving styrenes is illustrated in Scheme 3. Whereas titanium forms a bidentate complex 11 with the C-1 carbonyl and C-alkoxy oxygens, which leads to the dihydroindole (equation 1), boron trifluoride engages in monodentate complexation 12 with the sulfonyl nitrogen, leading to dihydrobenzofuran formation (equation 2) [3, 4]. Likewise, the reaction between 11 and an enol ether derived from 4-piperidone is depicted in equation 3 [5]. 

N I C K L Benzofurans Synthesis Synthesis of benzofurans from phenols and allyl halides. 

---