The degenerate 21-homododecahedryl cation

A Radical Version of the Bromo‐ and the Iodocyclization of Bis(homoallylic) Alcohols — The Synthesis of Halogenated Tetrahydrofurans by Stereoselective Alkoxyl Radical Ring Closures

“…. 5-Methyl-1-phenyl-4-hexen-1-ol (1a), [21] 5-methyl-2-phenyl-4-hexen-1-ol (1b), [25] 2-phenyl-4-hexen-1-ol (1f), [20] 3-phenyl-4-penten-1-ol (1h), [20] 2-bromo-2chlorodimedone, [34] diethyl 2-bromo-2-methylmalonate, [35] diethyl 2-iodo-2-methylmalonate, [35] 2,2Ј-dithiopyridine-1,1Ј-dioxide, [28] Nhydroxypyridine-2(1H)-thione, [28] (E)-4-phenyl-3-buten-1-ol, [58] and 1-chloro-5-methyl-1-phenyl-4-hexene [21] were prepared according to published procedures. Trapping reagents BrCCl 3 , n-BrC 6 F 13 , Br 2 C 2 Cl 4 , CHI 3 , n-C 4 F 9 I were obtained from commercial suppliers and were used as received.…”

“…[24] Treatment of this chloride with a 2.6-fold excess of 4-(p-chlorophenyl)-N-hydroxythiazole-2(3H)thione tetraethylammonium salt provided, upon work up of the reaction mixture, 57% of 4-(p-chlorophenyl)-N-(5methyl-1-phenyl-4-hexen-1-oxy)thiazole-2(3H)-thione (6a, entry 1, Table 1) and 1,2-bis[4-(p-chlorophenyl)-2-thiazyl]disulfane (23%, not shown in Table 1). [23] 2-, and 3-Phenylsubstituted bis(homoallylic) alcohols 1b, [25] 1c, and 1f [26] were esterified with p-toluenesulfonyl chloride in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) to furnish the corresponding tosylates (96% from 1b, 88% from 1c, and 83% from 1f, not shown in Table 1). [20,27] Treatment of these alkylating reagents with 4-(p-chlorophenyl)-Nhydroxythiazole-2(3H)-thione tetraethylammonium salt in anhydrous DMF afforded alkoxyl radical precursors 6b, 6c, and 6f [23] in 45Ϫ53% yield (entries 2, 3, 7, Table 1).…”

Pentagonal dodecahedranes. Novel substitution patterns— MS fragmentation and unsaturation

“…δ α-C 95.0 for monobromide, 95.6 for 1,16-dibromide, 95.0 for 1,6-dibromide 15-the regularities corroborated by Paquette for the monosubstituted series. 18 The mass spectra of these 1,6disubstituted dodecahedranes exhibit typical correlations with the nature of the C᎐X bond, e.g. external C᎐X versus internal C᎐C bond rupture.…”

“…Still, there is so far no information as to the fate of the missing 11% material (see Comments section). This selectivity was probed with the installation of other (pseudo)halogens (16)(17)(18)(19), O- (20)(21)(22), and N-substituents (23,24). The utilisation of the two sterically rather protected tertiary ester groups for side-chain modifications (alkyl substituents, 25-31) was also checked.…”

“…In contrast, the high percentage of oligomers formed along the route to 1,6-diiodide 17 (CF 3 CH 2 I, hν, 14%) was provisionally related to a relatively slow interception by voluminous I ؒ radicals giving a chance to, inter alia, the recombination of dodecahedral radicals. 14,17 En route to the 1,6difluoride 18 and the 1,6-di-O-and 1,6-di-N-functionalised dodecahedranes 20-24, using mostly proven procedures, 8, 18 generally no complications at the stage of the various (cationic) intermediates were met: the two-fold substitutions dichloride 16→difluoride 18 (AgBF The transformation of diester 7 and diamide 14 into bismethyl derivatives such as 25-31 was originally intended as a potential access to C 22 -bishomododecahedranes by two-fold ring enlargement. 21 While hydride addition to the sterically well-shielded ester groups of 7 (LAH) leading to 25 was rapid, the addition of the larger NH 2 Ϫ to give biscarboxamide 14 was problematic; with Weinreb's reagent (CH 3 AlClNH 2 ) 22 at ele- vated temperature a high yield (87%) was achieved.…”