Funktionalisierte Octabisvalene

Abstract

~ Functionalized OctabisvalenesQuadricyclanone (13) is the starting material for a five-step synthesis of 3-cyanooctabisvalene (24, 19% total yield), cyclooctatetraene for a six-step synthesis of (Z)-3,?-dicyanooctabisvalene (58,7% total yield).

Non-empirical calculations of NMR indirect carbon–carbon coupling constants. Part 9—Bicyclobutane-containing polycycloalkanes

“…Although the sign of J C,C D 13.6 Hz between bridgehead carbons of bicyclobutane moiety in octabisvalene (7) 6 was not determined experimentally, it could be safely regarded as negative based on the early EOM calculations by Galasso, 34 the present SOPPA results (Tables 5 and 6) and explicit analogy with the parent bicyclobutane 29,30 together with the relevant speculations in the original publication by Trupp et al 6 The numerical value of the bridgehead-bridgehead J(C,C) calculated by Galasso 34 for octabisvalene ( 11.9 Hz) agrees well with experiment 13.6 Hz 6 and the present SOPPA result ( 14.3 Hz). However, Galasso's EOM value of this coupling in the parent bicyclobutane ( 9.4 Hz) is obviously underestimated compared with the most reliable experimental data by Finkelmeier and Lüttke 30 ( 17.5 Hz) and with our best SOPPA calculations 3 ( 14.8 Hz).…”

“…Polycycloalkanes 1,2 and 5-7 are conformationally rigid having the following symmetry point groups: C s (5), C 2v (1,2,6) and D 2h (7). Hence octabisvalene (7) is the most symmetrical molecule in this series, possessing one inversion center, three principal second-order axes and three planes of symmetry.…”

“…In all geometric searches and calculations of spin-spin coupling constants Abelian symmetry point group D 2h was employed. 6 these two couplings were (erroneously) interchanged.…”

“…Two of the previous papers 2,3 in this series were devoted to bicyclobutane itself 2 and related bridged bicycloalkanes 3 and in this work we studied seven wellknown bicyclobutane-containing polycycloalkanes (1-7) with special focus on J(C,C) between bridgehead carbons, closely reflecting hybridization effects. Interest in tricyclopentane (1), 4 octabisvalene (7), 5 -7 other polycycloalkanes under consideration (2)(3)(4)(5)(6) 8 and related systems 9 stems also from their chemistry and applications in organic synthesis.…”

The reductive decyanation reaction: chemical methods and synthetic applications

“…The Li or Na/NH 3 system has been widely used in organic synthesis. [19][20][21][22][23][24][25][26][27] Rychnovsky investigated the alkylation and reductive decyanation of cyanohydrin acetonides such as 1 (Scheme 3). 28 The latter are key intermediates in the synthesis of polyene macrolide antibiotics such as roflamycoin, 29 17-deoxyroflamycoin 30 or filipin III.…”