419541-55-2Relevant academic research and scientific papers
Enantioselective Synthesis of cis-2,6-Disubstituted-4-methylene Tetrahydropyrans via Chromium Catalysis?
Bai, Jing,Chen, Bin,Zhang, Guozhu
supporting information, p. 1642 - 1646 (2020/10/19)
Enantioenriched 2,6-disubstituted 4-methylene tetrahydropyrans have been obtained via a two-step sequence consisting of a highly enantioselective chromium-catalyzed carbonyl 2-(trimethylsilyl methyl)allylation and Prins cyclization. Commercially available (2-(chloromethyl)allyl)trimethylsilane serves as the bifunctional linchpin to combine two aldehydes to assemble the 2,6-disubstituted pyrans. A variety of functional groups are compatible under the mild reaction conditions. The synthetic utility of this methodology was demonstrated by the asymmetric synthesis of 16 examples of homoallylic alcohol and 8 examples of 2,6-disubstituted 4-methylene tetrahydropyrans, including an advanced intermediate which could be transformed to natural product centrolobine via a known procedure.
A bidirectional SE′ strategy for 1,5- syn and 1,5- anti stereocontrol toward the synthesis of complex polyols
Williams, David R.,Claeboe, Christopher D.,Liang, Bo,Zorn, Nicolas,Chow, Nicholas S. C.
supporting information; experimental part, p. 3866 - 3869 (2012/09/22)
Studies report a bidirectional SE′ strategy applicable for the stereocontrolled synthesis of nonracemic 1,5-syn and 1,5-anti diols and their derivatives. Nonracemic 1,3,2-diazaborolidine auxiliaries are incorporated by chemoselective tin-boron exchange to provide reactive allylic boranes. The convergent pathway utilizes sequential reactions with two aldehydes producing stereochemical outcomes from cyclic, closed, and open transition state preferences, respectively. Synthesis of fragment 16 of peloruside A is accomplished in four steps from readily available aldehydes 9 and 13.
Efficient asymmetric catalysis of chiral organoaluminum complex for enantioselective ene reactions of aldehydes
Ooi, Takashi,Ohmatsu, Kohsuke,Uraguchi, Daisuke,Maruoka, Keiji
, p. 4481 - 4484 (2007/10/03)
Chiral organoaluminum complex 1 efficiently catalyzed the asymmetric hetero-ene reaction of commercially available 2-methoxypropene (2) with aldehydes under mild conditions to give the corresponding β-hydroxymethyl ketones 3 in good to excellent chemical
Pyran annulation: asymmetric synthesis of 2,6-disubstituted-4-methylene tetrahydropyrans.
Keck, Gary E,Covel, Jonathan A,Schiff, Tobias,Yu, Tao
, p. 1189 - 1192 (2007/10/03)
[reaction: see text] A reaction process for the asymmetric construction of a variety of cis or trans disubstituted pyrans is described. This sequences allows for the asymmetric convergent union of two aldehydes with silyl-stannane reagent 1 in a two-step
Sequential catalytic asymmetric allylic transfer reaction: Enantioselective and diastereoselective construction of tetrahydropyran units
Yu, Chan-Mo,Lee, Jae-Young,So, Byungran,Hong, Junghyun
, p. 161 - 163 (2007/10/03)
Useful tetrahydropyran units such as 3 can be prepared with high diastereoselectivity (d.r. > 30:1). A key step is the catalytic asymmetric allyl-transfer reaction from 1 to achiral aldehydes catalyzed by [{(R) binol}TiIV{OCH(CF3)2}2] to give 2 (90-97% ee). A second allyl-transfer reaction from 2 to a carbonyl compound leads to 3. binol = 2,2′-binaphthol.
