ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The bicyclic ketones 1-6 entered into diastereoselective (〉 95% d.e.) aldol reactions with a variety of aldehydes (Scheme 1 and Table 1). A representative series of aldols was converted (E)-selectively into α,β-unsaturated ketones by (i) spontaneous base-promoted dehydration (Scheme 1 and Table 2) and also by (ii) conversion into brosylate and base-mediated elimination with lithium diisopropylamide/N,N,N′,N′-tetramethylethylenediamine (LDA/TMEDA; Scheme 2). The simple α-methylidene ketones 17a and 18a were obtained via oxidation of the phenylselenides 19 and 20, respectively (Scheme 4). The tertiary aldol 27 was synthesized best by treatment of 1,3-diketone 26 with Me4Zr (Table 4). In this fashion, the facile retro-aldol reaction of 27 was suppressed effectively.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19930760604
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