New Spirans Containing a 1,5-Benzodithiepine System, Derived from Methylbenzenes. Conformational Transmission
摘要:
[GRAPHICS]A synthesis of three new spirans, derived from methylbenzenes, containing the 1,5-benzodithiepine system is reported. X-ray structure proved the identity of model monospiran 9. In the solid and liquid state, the conformation of the seven membered ring is chair, and the five-membered ring has the envelope conformation. The effect of conformational transmission in spirans 9 and 10 was observed, The synthesis of trispirans from hexamethylbenzene using the proposed scheme is also possible.
Solvent and leaving group effects on the mono- vs. Dialkylation of alkali salts of diethyl malonate with 1,2-bis-, 1,2,4,5-tetrakis- and 1,2,3,4,5,6-hexakis-(Halomethyl)benzenes. A new insight into selectivity control of malonester synthesis
protic (“acidic”) solvents favor monoalkylation whereas aprotic (“inert”) solvents support dialkylation of diethyl malonate carbanion, exactly opposite results have been obtained in the reaction of the dibromide 7, tetrabromide 4 and hexabromide 1 in ethanol and dimethyl sulfoxide, the former solvent preferring strongly dialkylation (cyclization) and the latter monoalkylation. Investigation in a broader
Diversity-oriented approach to novel spirocycles via 1,2,4,5-tetrakis(bromomethyl)benzene under operationally simple reaction conditions
作者:Sambasivarao Kotha、Rashid Ali
DOI:10.1016/j.tet.2015.07.008
日期:2015.9
4,5-tetrakis(bromomethyl)benzene in one step. We have also expanded this strategy to generate a variety of bis-spirocycles by treating the di-bromo intermediates with different AMCs under operationally simple reaction conditions.
[GRAPHICS]A synthesis of three new spirans, derived from methylbenzenes, containing the 1,5-benzodithiepine system is reported. X-ray structure proved the identity of model monospiran 9. In the solid and liquid state, the conformation of the seven membered ring is chair, and the five-membered ring has the envelope conformation. The effect of conformational transmission in spirans 9 and 10 was observed, The synthesis of trispirans from hexamethylbenzene using the proposed scheme is also possible.