The Formation of cis- and trans-Perhydrobenzofurans from 2-(2-Methoxycyclohexyl)ethanol Derivatives. Reactions Proceeding through Methoxyl Participation

A Synthetic Approach to Perhydro-3-isoquinolinones Bearing an Angular Methyl Group via Organocuprate Addition

“…Ozonolysis of 14 gave the diketone 15 in excellent yield. This two-step procedure allows substantially improved access to 15 avoiding alternative routes using readily decomposing iodides [8] or expensive reagents [9]. Subsequent condensation of precursor 15 under basic reaction conditions led to the Michael acceptor 11 [10].…”

“…This is achieved in both compounds by the formation of cyclically hydrogen-bonded dimers of symmetry C i : in the oxime 16b by molecular dimers linked via a six-membered ring Á Á ÁN±O±HÁ Á ÁN H ± O H ±H H Á Á Á (primed atoms are inversion related to unprimed ones, dots indicate hydrogen bonds), in the lactam 9b by molecular dimers linked via an eightmembered ring Á Á ÁO±C(1)-N±HÁ Á ÁO H ±C(1) H -N H ±H H Á Á Á. The hydrogen bond (9) 0.2213 (6) 0.4133(4) C (2) 0.7660 (7) 0.3589 (7) 0.3385(4) C (3) 0.6234 (7) 0.4430 (6) 0.2580(4) C(4) 0.6153 (8) 0.6133 (6) 0.3331(4) C (5) 0.4847 (9) 0.7014 (7) 0.2516(5) C (6) 0.2530 (8) 0.5599 (7) 0.1846(4) C (7) 0.2541 (8) 0.3849 (6) 0.1142(4) C (8) 0.3910 (7) 0.2912 (6) 0.1924 (3) C(9) 0.2826 (7) 0.2040 (6) 0.2933(4) C (10) 0.4079 (9) 0.1401 (7) 0.1035(4) C (11) 0.0667 (7) 0.0328 (7) 0.2458 (4) cis Fig. 4, the H-bonded dimers of 16b and 9b are analogous in shape and spatial arrangement and, hence, also in the triclinic unit cells, space group P " 1.…”

Furano compounds. XII. Synthesis of furano[2,3-b]xanthones

“…For the addition of a [2,[3][4][5]-fused furan ring, the essential step is to introduce a 2-formyl or 2-acetyl group into the 1,3-dihydroxyxanthone molecule. 1,3-Dihydroxyxanthone undergoes formylation to yield 1,3dihy droxy-4-f ormy lxanthone.2 However, acetylation of 1,3-dihydroxyxanthone under normal Friedel-Crafts or Fries conditions results in a mixture of products.…”

“…When heated with sodium acetate/acetic anhydride, 2h underwent cyclization with decarboxylation and acetylation yielding l-acetoxy-3methylfurano [4,5-5 [xanthone (3a). Hydrolysis with 5% alcoholic potash smoothly converted it into the required l-hydroxy-3-methylfurano [2,[3][4][5] Experimental Section l.S-Dihydroxy-Z-acetylxanthone.1-Freshly fused ZnCl™ (4 g) was dissolved in acetic acid (8 ml) by heating. Acetic anhydride (4 ml) and 1,3-dihydroxyxanthone (4 g) were added.…”

Cyclization of cis- and trans-2-(2-methoxycyclohexyl)ethanol to cis- and trans-perhydrobenzofurans

“…2-(2-Methoxyphenyl)ethanol was prepared in 76% yield by the above method from o-allylanisole.12 Reduction of 7 g of this material with hydrogen in 30 ml of acetic acid and 3.3 g of 5% rhodium on alumina gave, after the usual work-up and distillation, the following fractions: (1) bp 50-52°( 10 mm), 0.7 g; (2) bp co. 117°( 10 mm), 1.0 g; (3) bp 117°( 10 mm), 3.5 g, ti25d 1.4655. Examination by vpc showed that cut 1 was mainly cfs-perhydrobenzofuran, cut 2 was a mixture of cfs-perhydrobenzofuran (5) and cis-2-(2-methoxycyclohexyl)ethanol (3), and cut 3 was pure cfs-2-(2-methoxy cyclohexyl)ethanol.…”