Optically pure 1,3-diols from (2R,4R)- and (2S,4S)-1,2:4,5-diepoxypentane
摘要:
Optically pure (> 97% ee) (2R,4R)-1,2:4,5-diepoxypentane (1) and its enantiomer can be prepared in three steps from 2,4-pentanedione without the need for chromatographic purification. Diepoxide 1 is an efficient precursor to a wide variety of optically pure syn and anti 1,3-diols. Reaction with excess nucleophile gives symmetric[GRAPHICS]anti 1,3-diols in good yield. Reaction with a slight excess of alkyllithium under Ganem's conditions gives the monoepoxides 5 in good yield. Addition of a second nucleophile to monoepoxide 5 gives asymmetric anti 1,3-diols. Mitsunobu inversion of monoepoxide 5 followed by addition of a second nucleophile gives syn 1,3-diols. Optically pure syn and anti 1,3-diols are available from diepoxide 1 in one to three steps and good overall yield.
CYCLISATION PROCESS OF FORMING A MULTIPLE RING COMPOUND
申请人:Loh Teck Peng
公开号:US20100228058A1
公开(公告)日:2010-09-09
The present invention relates to a cyclisation process of forming a multiple ring compound from an isoprenoid compound. The cyclisation process involves reacting the isoprenoid compound with an acetal initiator under conditions sufficient to form the multiple ring compound. The isoprenoid compound is contacted with an initiator an optionally with a catalyst. Cyclisation occurs by reaction of the initiator with the isoprenoid compound. Cyclic acetal compounds wherein the acetal forms part of 6-membered unsaturated ring are also defined.
[EN] CYCLISATION PROCESS OF FORMING A MULTIPLE RING COMPOUND<br/>[FR] PROCÉDÉ DE CYCLISATION DESTINE A FORMER UN COMPOSE A CYCLES MULTIPLES
申请人:UNIV NANYANG
公开号:WO2007097719A1
公开(公告)日:2007-08-30
[EN] The present invention relates to a cyclisation process of forming a multiple ring compound from an isoprenoid compound. The cyclisation process involves reacting the isoprenoid compound with an acetal initiator under conditions sufficient to form the multiple ring compound. The isoprenoid compound is contacted with an initiator an optionally with a catalyst. Cyclisation occurs by reaction of the initiator with the isoprenoid compound. Cyclic aceta compounds wherein the acetal forms part of 6-membered unsaturated ring are also defined. [FR] La présente invention concerne un procédé de cyclisation destiné à former un composé à cycles multiples à partir d'un composé d'isoprénoïde. Le procédé de cyclisation comprend la mise en réaction du composé d'isoprénoïde avec un amorceur acétalique dans des conditions suffisantes pour former le composé à cycles multiples. Le composé d'isoprénoïde est mis en contact avec un amorceur, et éventuellement, avec un catalyseur. La cyclisation a lieu par réaction de l'amorceur avec le composé d'isoprénoïde. L'invention concerne également des composés cycliques d'acétal, l'acétal faisant partie d'un cycle insaturé à 6 chaînons.