Source:http://linkedlifedata.com/resource/pubmed/id/11596945
Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
18
|
| pubmed:dateCreated |
2001-10-12
|
| pubmed:abstractText |
Perspirocyclopropanated bicyclopropylidene (6) was prepared in three steps from 7-cyclopropylidenedispiro[2.0.2.1]heptane (4) (24% overall) or, more efficiently, through dehalogenative coupling of 7,7-dibromo[3]triangulane (15) (82%). This type of reductive dimerization turned out to be successful for the synthesis of (E)- and (Z)-bis(spiropentylidene) 14 (67%) and even of the "third-generation" spirocyclopropanated bicyclopropylidene 17 (17% overall from 15). Whereas the parent bicyclopropylidene 1 dimerized at 180 degrees C to yield [4]rotane, dimerization of 6 at 130 degrees C under 10 kbar pressure occured only with opening of one three-membered ring to yield the polyspirocyclopropanated (cyclopropylidene)cyclopentane derivative 19 (34% yield), and at the elevated temperature the polyspirocyclopropanated 2-cyclopropylidene[3.2.2]propellane derivative 20 (25 % yield). Perspirocyclopropanated bicyclopropylidene 6 and the "third-generation" bicyclopropylidene 17 gave addition of bromine, hydrogen bromide, and various dihalocarbenes without rearrangement. The functionally substituted branched [7]triangulane 28 and branched dichloro-C2v-[15]triangulane 32 were used to prepare the perspirocyclopropanated [3]rotane (D3h-[10]triangulane) 49 (six steps from 6, 1.4% overall yield) and the C2v-[15]triangulane 51 (two steps from 17, 41% overall). Upon catalytic hydrogenation, the perspirocyclopropanated bicyclopropylidene 6 yielded 7,7'-bis(dispiro[2.0.2.]-heptyl) (52) and, under more forcing conditions, 1,1'-bis(2,2,3,3-tetramethylcyclopropyl) (53). The bromofluorocarbene adduct 33 of 17 reacted with butyllithium to give the unexpected polyspirocyclopropanated 1,4-di-n-butyl-2-cyclopropylidenebicyclo[2.2.0]hexane derivative 37 as the main product (55% yield) along with the expected "third-generation" perspirocyclopropanated dicyclopropylidenemethane 38 (21% yield). Mechanistic aspects of this and the other unusual reactions are discussed. The structures of all new unusual hydrocarbons were proven by X-ray crystal structure analyses, and the most interesting structural and crystal packing features are presented.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
|
| pubmed:month |
Sep
|
| pubmed:issn |
0947-6539
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
17
|
| pubmed:volume |
7
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
4021-34
|
| pubmed:dateRevised |
2009-8-4
|
| pubmed:year |
2001
|
| pubmed:articleTitle |
Spirocyclopropanated bicyclopropylidenes: straightforward preparation, physical properites, and chemical transformations.
|
| pubmed:affiliation |
Institut für Organische Chemie, Georg-August-Universität Göttingen, Germany. armin.demeijere@chemie.uni-goettingen.de
|
| pubmed:publicationType |
Journal Article
|