Zur Chemie einiger [4.1.1]‐ und [3.1.1]Propellane

Abstract

Die [4.1.1]Propellane 2a und b und die [3.1.1]Propellane 3,4a-c, 5 und 6 isomerisierten bei thermischer Belastung zu den 1,3-Dienen 7, 10, 11, 12 und 13. Die Geschwindigkeit diescr Umwandlungen wurde durch Spuren unbekannter elektrophiler Agenzien stark erhoht; Zusatz von 1,4-Diazabicyclo[2.2.2]octan zu den Thermolyse-Losungen schaltete die RG-beschleunigenden Effekte praktisch vollstindig aus. Die gezielte Umlagerung der Propellane durch elektrophile Katalysatoren vollzog sich bei Raumtemperatur unterschiedlich rasch. wobei wieder die Diene 7 und 10-13 als Hauptprodukte entstanden. Eine Sonderstellung nahmen Chlortrimethylsilan und Siliciumtetrachlorid ein; diese Verbindungen bewirkten, eingesetzt im zehnfachen UberschuD, die Isomerisierung der Propellane in die Norcarene 14, 19, 20a und 23. Die Addition von Methanol unter Siurekatalyse an 2a ergab den Methylether 26, wahrend die Anlagerung von Eisessig bzw. von Quecksilberacetat an 5 zur Bildung der Acetate 27a/b bzw. 27c/d fiihrte. Die Radikalketten-Addition von einigen Thiolen und von Bromtrichlormethan an 2a erbrachte die Norpinan-Derivate 29a-d; beim Einwirken von Ethanthiol auf 4c entstand neben 30 auch das Bisaddukt-Gemisch 31a/b. Diimin reduzierte 4c zu 33, wahrend Lithiumalanat die Kohlenstoff-Sauerstoffbindung von 4a-c zu den Hydroxy[4.1.1]propellanen 381-c spaltete.On heating, the [4.l.l]propellanes 2a and b and the [3.l.l]propellanes 3,4a-c, 5, and 6 were isomerized to the 1,3-dienes 7, 10, 11, 12, and 13. The rates of these rearrangements were strongly enhanced by traces of unknown electrophilic reagents. Addition of 1,4diazabicyclo[2.2.2]octane to the thermolysis solutions eliminated the rate accelerating effects completely. The intended rearrangement of the propellanes by electrophilic catalysts at room temperature proceeded under varying rates with the formation of the dienes 7 and 10-13 as the main products. An exceptional behavior was shown by chlorotrimethylsilane and by tetrachlorosilane, which when used in tenfold excess isomerized the propellanes to the norcarenes 14, 19, 2Oa, and 23. The addition of methanol to 2a under acid catalysis afforded the methyl ether 26, whereas the reaction of acetic acid and of mercuric acetate led to the formation of the acetates 27a/b and 27c/d. The radical chain addition of some thiols and of bromotrichloromethane to 2a produced the norpinane derivatives 29a -d. The reaction of ethanethiol with 4c yielded besides 30 a mixture of the bisadducts 31a and b. 4c was reduced by diimine to give 33. The carbon-oxygen bond of 4a-c was cleaved by lithium aluminium hydride leading to the hydroxy[4.1 .l]propellanes 38ac.

Synthesis and Reactivity Studies of 2,4-(Dimethylmethano)-2,4-didehydroadamantane: A Comparison with an Unsubstituted Analog

“…For and 13C NMR spectra (vide supra) and the reactivity studies 1 was dissolved under dry nitrogen in anhydrous benzene-dg (0.35 mL), and the resulting solution was transferred via syringe into an NMR tube which was flushed previously with dry nitrogen: IR (film KBr) 3035,3010,2930,2860,1470,1175,590,515,435 cm-1; Raman (neat) 1146 (m), 842 (m), 763 (vs), 645 (m) cm-1; 1H NMR (CgDg) 2. 93-2.33 (m, 3 ), 1.99-1.46 (m, 9 ), 1.28 (s, exo CH3), 1.08 (s, endo CH3); 13C NMR (CgDg) 59.4 (d, Hz, C-5), 56.6 (dd, Jc-h = 128 and 131 Hz, C-10), 56.0 (s, C-3), 36.2 (t, Jc-h = 129 Hz, C-8 and C-ll), 35.8 (d, Hz, C-l and C-9), 34.1 (s, C-2 and C-4), 32.1 (t, Jc-H = 128 Hz, C-6), 26.0 (d, Jc-h = 134 Hz, C-7), 22.0 (q, Jc-h = 126 Hz, C-12), 19.8 (q, Jc-h = 126 Hz, C-13); MS m/z (rel intensity) 174 (M+, 100), 159 (27), 145 (22), 133 (28), 119 (43), 117 (38), 105 (54), 91 (89), 79 (50), 77 (35).…”

Acid-Catalyzed Cyclization of Anthracenol Derivatives to Homotriptycenes

“…Cristol and co-workers 19 synthesized homotriptycene and its derivatives by ring enlargement of 1-aminomethyltriptycene, but the route was lengthy and required a tedious separation from the concomitant isomers. Szeimies et al 20 reported a unique route for the preparation of homotriptycenes using a thermal dehydrogenation of anellated dibenzohomobarrelene, but its application is limited because of the multistep preparation of the starting propellane and the restricted possibility for substituent variations in the homotriptycene skeleton. Saito et al 21 reported an alternative method using the cycloaddition of strained benzocyclopropene to anthracenes.…”

In Quest of a Prismene. Organolithium-Induced Desulfonylation on Strained Hydrocarbons

“…The last 10 years have witnessed many successful efforts to prove the existence of highly strained olefins which violate Bredt's rule. 1a-c Among them are tricyclo[4.1.0.0 2,7 ]hept-1(7)-ene ( 1 ), 2a-e and dehydroquadricyclanes, 3a-g such as 2 and 1,2-dehydrocubane ( 3 ) 4a,b to name only a few. All of them are severely bent olefins with very short life-times.…”

“…The products 15 and 16 point to a common intermediate to which the addition of n -BuLi can occur in two different ways. A first possible explanation is provided by the reaction sequence indicated in Scheme with 18 as intermediate. − A [2 + 2]-cycloreversion and subsequent hydrolysis leads to two different products. This assumption seemed reasonable because similar bridgehead olefins have been shown to be intermediates in other reactions, in which they were trapped by anthracene and furane derivatives.…”