Versatilechiralbuildingblocks for the construction of chiral natural products bearing a secondarymethylgroup have been efficiently prepared from (S)-O-benzylglycidol.
Highly Stereoselective C–C Bond Formation by Rhodium-Catalyzed Tandem Ylide Formation/[2,3]-Sigmatropic Rearrangement between Donor/Acceptor Carbenoids and Chiral Allylic Alcohols
作者:Zhanjie Li、Brendan T. Parr、Huw M. L. Davies
DOI:10.1021/ja303023n
日期:2012.7.4
The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C-Cbond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh(2)(DOSP)(4) and the chiral alcohol.
This paper describes the enantioselective synthesis of key fragments (12, 18, 24, and 35) for the synthesis of aplysiatoxin (1a), a potent cancer promoter, and their convergent assembly to Kishi's aldehyde (2). Since 2 has already been transformed into 1a in a short step, its synthesis constitutes a formal totalsynthesis of 1a
The Regio‐ and Stereospecific Intermolecular Dehydrative Alkoxylation of Allylic Alcohols Catalyzed by a Gold(I) N‐Heterocyclic Carbene Complex
作者:Paramita Mukherjee、Ross A. Widenhoefer
DOI:10.1002/chem.201203987
日期:2013.3.4
AgClO4 catalyzes the intermolecular dehydrative alkoxylation of primary and secondaryallylic alcohols with aliphatic primary and secondary alcohols to form allylic ethers. These transformations are regio‐ and stereospecific with preferential addition of the alcohol nucleophile at the γ‐position of the allylic alcohol syn to the departing hydroxyl group and with predominant formation of the E stereoisomer
Stereoselective synthesis of key fragments for the synthesis of aplysiatoxin has been achieved. All the stereogenic carbons contained in fragments B≈E were elaborated on the basis of [2,3] Wittig rearrangement and titanium-mediated asymmetric epoxidation.