Baylis-Hillman Reaction: Magnesium Bromide as a Stereoselective Reagent for the Synthesis of [E]- and [Z]-Allyl Bromides

Total Synthesis of (−)-Spirotryprostatin B and Three Stereoisomers

“…The preparation of 18 began with allylic alcohol 15. [25] The acetate derivative of 15 reacted cleanly with MgBr 2´E t 2 O to give the primary allylic bromide, [26] which was displaced with acetate to provide (E)-dienoate 16. Conversion of 16 into the siloxycarboxylic acid and coupling [27] of this intermediate with 2-iodoaniline provided 17 in excellent overall yield.…”

TMSOTf-Catalyzed Stereoselective Isomerization of Acetates of the Baylis - Hillman Adducts

“…[1][2][3][4][5][6] The Baylis-Hillman reaction is an important carbon-carbon bond forming and atom economy reaction, providing a useful class of molecules possessing chemospecific functional groups (Equation 1) which have been successfully used in a variety of stereoselective processes. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] As a part of our research program aimed at the development of the Baylis-Hillman reaction [14][15][16][17][18][19][20] as a source of stereo-selective processes, we herein report trimethylsilyl trifluoromethanesulfonate catalyzed stereoselective isomerization of the acetates of the Baylis-Hillman adducts, i.e. methyl 3-acetoxy-3-aryl-2-methylenepropanoates and 3-acetoxy-3-aryl-2-methylenepropanenitriles into methyl (2E)-2-(acetoxymethyl)-3-arylprop-2-enoates and (2E)-2-(acetoxymethyl)-3-arylprop-2-enenitriles, respectively.…”

A convenient and stereoselective synthesis of (Z)-allyl selenides via Sm/TMSCl system-promoted coupling of Baylis-Hillman adducts with diselenides

“…The adducts of the reaction, 3-hydroxy-2-methylene-alkanoates (derived from acrylate esters), have been widely utilized as important precursors for stereoselective synthesis of trisubstituted alkenes (Basavaiah et al, 1996;. To date, a series of heteroatom-substituted allylic derivatives transferred from Baylis-Hillman adducts have been reported, among which include allyl halides (Basavaiah et al, 1995;Chavan et al, 1997;Yadav et al, 2001), allyl sulfides (Calò et al, 1988), allyl amine (Das et al, 2005a), allyl ethers (Roy et al, 2000), allyl phosphonates (Janecki and Bodalski, 1990), and allyl borates (Kabalka et al, 2004), etc. However, to the best of our knowledge, no literature on the synthesis of Baylis-Hillman adduct-derived allyl selenides has been (Liu et al, 2005;2006) and application of samarium reagents in organic synthesis (Zhou and Zhang, 1999;Lu and Zhang, 1999), we report here a simple and convenient procedure for the stereoselective synthesis of (Z)-allyl selenides via one-pot reaction of diselenides with Baylis-Hillman adducts promoted by samarium-trimethylsilyl chloride system under mild conditions.…”