110569-60-3Relevant academic research and scientific papers
Phosphorus compounds 97. Synthesis of polycyclic phosphorus cage compounds containing diphosphirane and phosphirane units by tandem Diels-Alder and ene reactions: a contribution to the cycloaddition and enophile chemistry of phosphaalkynes
Heydt, Heinrich,Bergstraesser, Uwe,Faessler, Rainer,Fuchs, Eberbard,Kamel, Nasr,et al.
, p. 652 - 668 (2007/10/02)
When the open-chain 1,3-dienes 14a-k are allowed to react with the phosphaalkyne 13 in a molar ratio of 1:2 under thermal conditions, the 1,7-diphosphatricyclo2,7>oct-3-enes 19 and/or 20 are formed.The formation of isomers is attributable to the initial Diels-Alder reaction since both the subsequent ene reaction (specific formation of 17, 18) and the concluding intramolecular Diels-Alder reaction (-> 19, 20) proceed specifically.The constitutions of the tricyclic systems incorporating a diphosphirane unit were confirmed by NMR spectroscopic data and a crystal structure analysis of 19a (=20a).The s-cis-configurated 1,3-butadienes 14l-u react similarly with 13 (Diels-Alder reaction -> phospha-ene reaction -> intramolecular Diels-Alder reaction) to furnish the tetracyclic products 19l-u (=20l-u).The same reaction sequence is also responsible for the regiospecific formation of the diphosphatetracyclic systems 19v-y from the reactions of 13 with the semicyclic 1-vinylcycloalk-1-enes 14v-y.In principle, phosphaalkynes such as 13, independent of the above-mentioned reaction sequence, are suitable for use as enophiles in ene reactions.This is illustrated by the conversions 21 + 13 -> 22 and 21 + 22 -> 23.The cyclohexa-1,4-diene 24a reacts with 13 to furnish the phosphatricyclooctene 29a, a result in complete harmony with the reaction sequence 15/16 -> 19/20.Product 29a now contains a phosphirane unit instead of the diphosphirane in the former substances.The regioselectivity of the ene reaction is lost when the substituted 1,4-dienes 24b-e and the annelated derivatives 24f,g are used as reaction partners for 13.The cyclohexa-1,4-diene 24b participates in a completely nonspecific reaction with 13 (-> 29b, 30b, 31b, 32b).Keywords: phosphaalkyne / phosphirane / diphosphirane / cycloaddition / phospha-ene reaction / tandem reaction / intramolecular Diels-Alder reaction
