Reactions of Polycyclic Ketones with Dimethoxycarbene; a Convenient Route for a ‘One‐Pot’ Preparation of Some α‐Hydroxycarboxylic Acid Esters |
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| Authors: | Jarosław Romański Grzegorz Mlostoń Heinz Heimgartner |
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| Affiliation: | 1. University of ?ód?, Department of Organic and Applied Chemistry, Narutowicza 68, PL‐90‐136 ?ód?, (phone: (48?42) 635?57?69;2. fax: (48?42) 678?16?09);3. Organisch‐chemisches Institut der Universit?t Zürich, Winterthurerstrasse 190, CH‐8057 Zürich |
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| Abstract: | ![]()
Polycyclic ‘cage’ ketones, such as pentacyclo[5.4.0.02,6.03,10.05,9]undecan‐8‐one ( 10 ), pentacyclo[5.4.0.02,6.03,10.05,9]undecane‐8,11‐dione ( 11 ), and adamantan‐2‐one ( 16 ) were treated with the nucleophilic dimethoxycarbene (DMC; 1 ), which was generated thermally from 2,5‐dihydro‐2,2‐dimethoxy‐5,5‐dimethyl‐1,3,4‐oxadiazole ( 4a ) in boiling toluene. In this ‘one‐pot’ procedure, the α‐hydroxycarboxylic acid ester 12 or a corresponding derivative 15 or 17 was obtained (Schemes 4–7). Additionally, ‘cage’ thione 21 was treated with DMC under the same conditions yielding dimethoxythiirane 22 (Scheme 8). Subsequent hydrolysis or desulfurization (followed by hydrolysis on silica gel) of 22 gave α‐mercaptocarboxylate 25 and the corresponding desulfurized ester 24 , respectively. In all cases, the addition of DMC occurred stereoselectively, and the addition from the exo‐face is postulated to explain the structures of the isolated products. |
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| Keywords: | Carbenes, dimethoxy‐ Carboxylates, α ‐hydroxy‐ ‘ Cage’ compounds Ketones, polycyclic Thioketones |
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