摘要:

AbstractThe title compounds 2,2‐ethano‐1‐methylene and 1,1‐ethano‐2‐methylene‐1,2,3,4‐tetrahydronaphthalene (13and14respectively) were synthesized by the Wittig reaction from the corresponding ethano‐tetralones (16) and (19) which were, in turn, prepared from the respective α‐ and β‐tetralones (15) and (18). It is shown that the reaction of (13) with TCNE at 0° yields the corresponding [2 + 2] cycloaddition adduct (20), isomerizing thermally to the formal [2 + 5] cycloaddition adduct (21). Compound (13) reacts with N‐tosylisocyanate (TIC) and with N‐phenylsulfonylisocyanate (PSI) to a 4:1‐isomeric mixture of (Z)‐ and (E)‐acryloamides (24) and (26), respectively. The reaction of (14) with TCNE at 0° leads to the [2 + 5] cycloadduct (30), while with (TIC) and (PSI) the corresponding tricyclic adducts (28a) and (28b) result. Bromination of (16) with NBS yielded the respective 4‐bromo‐2,2‐ethano‐1‐tetralone (31) which gave, upon dehydrobromination with the aid of DBU, the naphtho‐dihydrofurane derivative (34). The latter was formed most likely via facile cyclopropylketone upon dihydrofurane rearrangement of an initially formed 2,2‐ethano‐1‐oxo‐1,2‐dihydronaphthalene (32) which was desired for the formation of (33). Structures of all new compounds were assigned on basis of analyt

ISSN:0021-2148    

DOI:10.1002/ijch.198200012

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe electronic structures of the title compounds were calculated byab initioSTO‐3G minimal basis set following a MINDO/3 total geometry optimization of both. Their different reactivities towards electrophiles is suggested to result from different frontier (HOMO) orbital densities on the relevant atoms. Both MINDO/3 and STO‐3G calculations give similar results for the HOMO structures, where frontier density is comparable on exocyclic methylene and ethano bridge atoms in the 1,1‐ethano 2‐methylene analog, and much higher on the methylene than on the cyclopropyl atoms in the second molecule. Relative rates of reaction are also di

ISSN:0021-2148    

DOI:10.1002/ijch.198200013

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractVinylaziridines undergo ring expansion reactions which in case of divinylaziridines lead to dihydroazepines. Addition of 2‐phenyl‐2‐vinyl‐aziridine10ato dimethyl acetylene dicarboxylate provides a facile method ofin situgeneration of a divinylaziridine and leads to isolation of an azepine derivative. Likewise we show that cycloaddition of10aproceeds even with olefinic nitriles, sulfones and esters with formation of tetrahydroazepines. However, when the substrates are unsaturated nitro compounds or ketones, a novel rearrangement to open chain enamine derivatives takes place. Deuterium labelling in the β‐nitrostyrene substrate and in the vinylaziridine provide evidence for a retro‐ene reaction mechanism leading to the rearrangement. These data provide a framework for assessing the factors that guide the reactions either towards formation of seven‐membered ring azepine derivatives or toward open‐chain rea

ISSN:0021-2148    

DOI:10.1002/ijch.198200014

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.198200015

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.198200001

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY