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Synthesis and Trapping of Transient 1, 2‐Diselones To Yield 1, 4‐Diselenin Derivatives: Calculated Structures of 1, 2‐Diselones, 1, 2‐Diselenetes and Their Sulfur Analogues
Author(s) -
Chesney Antony,
Bryce Martin R.,
Yoshida Shimon,
Perepichka Igor F.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/(sici)1521-3765(20000403)6:7<1153::aid-chem1153>3.0.co;2-n
Subject(s) - chemistry , dimethyl acetylenedicarboxylate , trapping , yield (engineering) , bicyclic molecule , adduct , sulfur , ring (chemistry) , stereochemistry , fragmentation (computing) , computational chemistry , organic chemistry , cycloaddition , materials science , metallurgy , ecology , computer science , biology , operating system , catalysis
Two conceptually different routes to transient 1,2‐diselones are reported: 1) via ring fragmentation of the 1,4,2‐diselenazine system 6 , and 2) by the tributylphosphane‐induced depolymerisation of the shelf‐stable organoselenium polymer 15 . Evidence for the intermediacy of 1,2‐diselone species 7 and 16 is provided in both cases by in situ trapping with dimethyl acetylenedicarboxylate (DMAD) to yield 1,4‐diselenin derivatives. The route via 15 is especially expedient and trapping of 16 is efficient. Subsequent reactions of adduct 17 afford [1,2‐ethanediylbis(diphenylphosphane)][5,6‐bis(methoxycarbonyl)‐1,4‐diselenin‐2,3‐dithiolato]nickel( IV ) ( 20 ). Theoretical calculations at Hartree‐Fock (HF) and Møller‐Plesset electron‐correlated levels (MP2) suggest that the cyclic 1,2‐diselenete structure 7 c is significantly more stable than the acyclic 1,2‐diselone structure 7 a . For the bicyclic system 16 , the difference in energy between the cyclic and acyclic structures is considerably reduced due to the conformational rigidity imposed by the fused 1,3‐dithiole ring. In contrast, the acyclic structures of the 1,2‐dithione analogues 13 a and 25 a are computed to be more stable than their corresponding cyclic 1,2‐dithiete structures 13 c and 25 c .