Reaktionen von polyhalogenierten benzocyclobutenen mit alkoholaten und thiolaten

Roedig, Alfred; Ganns, Eva-Maria; Henrich, C.

doi:10.1016/s0040-4020(01)91840-x

Cited by 3 publications

(2 citation statements)

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“…Nucleophilic substitution of perchlorobenzocyclobutene ( 300a , R = Cl; 300d , R = Ph) by methanolic sodium hydroxide occurs first at the benzene nucleus, giving 546 , and then at the four-membered ring to afford 547 . However, reaction of 300a and 300d with thiolates in DMSO gave only 548 and 549 (Scheme ) 127 …”

Section: G Miscellaneous Reactionsmentioning

confidence: 99%

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Cyclobutarenes and Related Compounds

2003

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A general method for the synthesis of cyclobutarenes involves 1,4-elimination from adjacent benzylic positions, followed by ring closure of the resulting o-quinodimethane. The earliest report in which an o-quinodimethane was implicated was the reaction of R,R,R′,R′-tetrabromo-o-xylene (4) with iodide to give the 1,2-dibromocyclobutarene 6, via o-quinodimethane 5. Treatment of 6 with NaI in acetone gave diiodide 7, which on catalytic reduction gave 1 (Scheme 1). [15][16][17] Cava and co-workers confirmed that 5 was an intermediate by trapping experiments using sev-eral dienophiles. 18 A similar procedure has been used to prepare 1,2-diphenylcyclobutarene. 19 Heterocyclic analogues may also be prepared by the 1,4-elimination of halogen from suitable precursors. Compounds 9 and 11 have been synthesized from 8 and 10, respectively, as illustrated in Scheme 2. 20 A variation of the method involves the conversion of R-alkyl-R-bromosulfones into cyclobutarenes using tetrabutylammonium fluoride (TBAF) in acetonitrile at 20-25 °C to effect the elimination. 21 The desired cyclobutarene is often accompanied by olefinic side products, as illustrated in the preparation of cyclobutarene 13, which is accompanied by 14 (eq 1) (Table 1). Anil K. Sadana was born in Panipat, India. He did his M.Sc (1990) and M. Phil (1992) from Kurukshetra University, India. He obtained his Ph.D. degree in 1999 under the guidance of Prof. Om Prakash. His Ph.D. work focused on the utility of hypervalentiodine reagents in the synthesis of heterocyclic compounds. He then joined Prof. W. E. Billups lab as postdoctoral research associate in 2000. He is presently working on small ring compounds and carbon nanotubes. Rajesh Kumar Saini was born in 1966 in Ambala, India. He received his masters degree in 1989 and his Ph.D. in 1996 from Kurukshetra University, India. After his doctorate he moved to the United States for his postdoctoral studies. After a brief stay at Sam Houston State University he joined Rice University, where he is working as a Research Scientist in the laboratories of Prof. W. E. Billups and Prof. Richard E. Smalley. His research has concentrated on small ring compound and the development of carbon nanotube chemistry. W. E. Billups was born in 1939 in Huntington, West Virginia. He received his B.S. in Chemistry Degree from Marshall University in 1961. This was followed by a period in industry after which he entered the graduate school of the Pennsylvania State University in 1968 and received the Ph.D. in 1970. He then joined the chemistry department at Rice University. He served as the Department Chair from July 1985 until December 1991. His research interests are divided among the areas of small-ring compounds, reactive intermediates, chemistry of free metal atoms and more recently fullerene and carbon nanotube chemistry.

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Section: G Miscellaneous Reactionsmentioning

confidence: 99%

“…However, reaction of 300a and 300d with thiolates in DMSO gave only 548 and 549 (Scheme 127). 397 Nickel-catalyzed cyclooligomerization of 6 in THF yielded mainly the transoid and cisoid dimers 550. [398][399][400] These compounds rearrange to 551 upon heating or by treatment with silver ion.…”

Section: G Miscellaneous Reactionsmentioning

confidence: 99%