Resin acids. XXVIII. Rearrangements in the photolevopimaric acid series. Paradigm of bicyclo[2.2.0]- and bicyclo[2.1.1]hexane chemistry

Abstract

aluminum hydride; ferf-butyl alcohol, dimethyl sulfoxide, pyridine, and hexamethylphosphoramide (HMPA) were distilled from calcium hydride; dichloromethane, carbon tetrachloride, dlodomethane, and methyl iodide were distilled from phosphorus pentoxide; ammonia was distilled from the tank and then from a blue lithium or sodium solution; acetone was analytical reagent grade distilled from potassium permanganate; formic acid was distilled from boric anhydride. "Petroleum ether" refers to the "Analyzed Reagent" grade hydrocarbon fraction, bp 30-60°, which is supplied by J. T. Baker Co., Phillipsburg, N.J., and was not further purified.Reactions described as run under nitrogen or argon employed a mercury bubbler arranged so that the system could be alternately evacuated and filled with the inert gas and left under a positive pressure.Microanalyses were performed by Spang Microanalytical Laboratory, Ann Arbor, Mich. (32) In cases where products were isolated 'by solvent extraction", the procedure generally followed was to extract the aqueous layer with several portions of the indicated solvent; then the organic layers were combined and washed with water, followed by saturated brine. The organic layer was dried over anhydrous sodium or magnesium sulfate, then filtered, and the solvent was evaporated from the filtrate under reduced pressure (water aspirator) using a rotary evaporator. The use of the terms "base wash" or "acid wash" indicate washing the combined organic layers with saturated aqueous sodium bicarbonate solution or with dilute aqueous hydrochloric acid, respectively, prior to the aforementioned washing with water. (33) F. Uhlig and H. R. Snyder, Adv. Org. Chem., 1, 35 (1960).(34) Preparative GLC under the same conditions described above31 except that the following columns were used: (a) 5 % SE-30 on Chromosorb W AW-DMCS (6 ft X 0.125 In); (b) 10% Carbowax 20M on Chromosorb W AW-DMCS (10 ft X 0.25 in). ( 35) For spectra, see R. I.

Synthese von (+)‐Taxodion

“…(34), 342 (90), 340 (33, 259 (11). 19.0 g (44.4 mniol) 5 wurden in 300 ml absol. CH2C12 gelost, mit 200 ml absol.…”