A new method for the synthesis of mixed orthoesters from O-allyl acetals

✍ Scribed by Stanisław Krompiec; Robert Penczek; Piotr Bujak; Ewelina Kubik; Joanna Malarz; Mateusz Penkala; Michał Krompiec; Nikodem Kuźnik; Hieronim Maciejewski

• Publisher: Elsevier Science
• Year: 2009
• Tongue: French
• Weight: 284 KB
• Volume: 50
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2008.12.110

✦ Synopsis

Two new methods for the synthesis of orthoesters and compounds containing an orthoester moiety (dihydroisoxazoles) are presented. Mixed orthoesters of general formulas RC(OR 1 )(OR 2 ) 2 and RC(OR 1 )-(OR 2 )(OR 3 ) were prepared via addition of ROH (R = Bu or m-methylphenyl) to O-allyl acetals (acrolein acetals: diethyl or cyclic, i.e., 2-vinyl-1,3-dioxanes or dioxolanes). The catalytic systems for these reactions were generated from [RuCl 2 (PPh 3 ) 3 ] and Na 2 CO 3 ; {[RuCl 2 (COD)] x } or {[OsCl 2 (1,5-COD)] x }, PPh 3 , and Na 2 CO 3 . Compounds containing an orthoester moiety (dihydroisoxazoles) were prepared via tandem isomerization of O-allyl acetals (to O-vinyl acetals) catalyzed by ruthenium complexes followed by cycloaddition to in situ-generated 2,6-dichlorophenylnitrile oxide.