Sterol Models. I. 3a-Methyl-cis- and -trans-hexahydroindans and their -3a-Methyl-d₃ Analogs¹

Abstract

The independent and unequivocal syntheses of 3a-methyl-«'s-and -irarcs-hexahydroindan and several of their deuteromethyl analogs have been achieved through stereospecific reactions. Through a Diels-Alder synthesis, a methoxycarbonyl group was locked into the «'^-configuration at the angular position of a tetrahydroindan and transformed, via the saturated angular ester, hydroxymethyl and corresponding tosylate of the latter, to the desired 3a-methyl-«s-hexahydroindan. Byemploying the appropriate combinations of lithium aluminum hydride and lithium aluminum deuteride, the mono-, diand trideuteromethyl-«s-hexahydroindans also were obtained. 3a-Methyl-<ro«t-hexahydroindan was attained through 4aethoxycarbonyl-<ra»s-3,4,4a,5,6,7,8,8a-octahydro-2-[lH]-naphthalenone. After the oxo group was converted to the corresponding dioxolane, the angular ester was reduced to the hydroxymethyl group and then to the angular methyd group through the tosylate and benzyl thioether. After hydrolysis of the dioxolane, the resulting methyldecalone was oxidatively7 cleaved, reeyclized to the corresponding hydrindanones and finally reduced to 3a-methyl-Zra«s-hexahydroindan. By starting with the dioxolane ester and using lithium aluminum deuteride and deuterated Raney nickel, the corresponding deuterium containing analogs were obtained.

Propellanes. 17. Bridgehead olefins via solvolysis of 10,10-dibromo[4.3.1]propellanes

“…The "kinetic" ratio (after 1 min-very little difference after 2 min reaction time) was 2.7:1.0:1.1 (6:22:32), while the "thermodynamic" ratio (almost the same after 1 or 5.5 h) was 0.1:1.0:0.2. It is not known if 6 went directly to 22 or funneled through 32.…”

“…This procedure afforded 440 mg of crude oil, which was chromatographed on silica gel. The products, the yields of which are shown in eq 8, were eluted in the following order: 36, 33 + 34 + 35, 6, 32, 22. l-Hydroxy-6-acetoxy-10a-bromobicyclo[4.3.1]dec-3-ene (22): mp 88-89.5 °C;IR (CDCfi) 3570, 3450, 3020, 1735, 1670, 1255 cm"1; NMR (CDCfi) 5.47 (m, 2 ), 5.08 (s, H( 10)), 3.1-1.5 (m, with acetate s at 2.02, 14 H). Anal.…”

Cycloalkenylboranes as Highly Reactive and Selective Diels−Alder Dienophiles. A Simple Synthesis of Bridgehead Bicyclic Alcohols

“…The low reactivity of cyclohexenones is notorious, though many of the problems have been solved by employing Lewis acid catalysis , Cyclopentenes are more reactive than cyclohexenes, and the best success has been obtained either with formyl as the activating group 3,5 or with highly reactive dienes such as Danishefsky's diene. −

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“…to the ring appear somewhat less reactive, and there is a history of these dienophiles either failing to react in Diels-Alder reactions or affording low yields after prolonged heating. 2,3 Cyclopentenes are more reactive than cyclohexenes, 4 and the best success has been obtained either with formyl as the activating group 3,5 or with highly reactive dienes such as Danishefsky's diene. [6][7][8] Trivalent boron atoms are powerful activating substituents for dienophiles and impart a number of unusual and useful properties to the Diels-Alder reactions of vinylboranes and acetylenic boranes.…”

Proton magnetic resonance and phosphorus-31 nuclear magnetic resonance studies of substituted phospholan-3-one 1-oxides

“…The infrared spectrum displayed a strong band for the C-O at 1725 cm-1 and a shift in the P-»-0 vibration to 1179 cm-1 (Table V). 13 Pmr analysis did not afford a singlet indicative of the other Omethyl derivatives (15)(16)(17)(18) but instead a doublet appeared ( 1.76 ppm, JpccHa = 12 Hz) in addition to the doublet for the methyl at C-4 ( 1.34 ppm, Jhcch = 7.0 Hz).14 Interestingly, the…”