In the Still-Wittig rearrangement, stannylated methyl (E)-allylic ethers having an aliphatic side chain (1a-c) exhibited the usual similar stereoselectivity, although the poor stereoselectivity was remarkably improved by the assistance of an alkoxy moiety on the alkenyl chain. A stannylated methyl (Z)-allylic ether bearing an alkoxy moiety on the alkenyl chain (1e) also showed a high E selectivity
Stereochemical course of the [2,3]-sigmatropic rearrangement of substituted propargyl n,n-dialkylamidosulfoxylates. X-ray molecular structure of [S*, (S)R*]-4-[(1,4,4-trimethyl-1,2-pentadienyl)sulfinyl]-morpholine.
作者:Jean-Bernard Baudin、Itka Bkouche-Waksman、Sylvestre A. Julia、Claudine Pascard、Yuan Wang
DOI:10.1016/s0040-4020(01)86400-0
日期:1991.1
By the reaction with three N,N-dialkylanidosulfenyl chlorides 2 bearing representative sizes for the R group on the nitrogen atom, several substituted secondary propargylic alcohols (la-f) have been converted into the corresponding pairs of diastereoisomeric allenic sulfinamides 3a-n and 3′a-j,l.m. Their ratios have been determined by 1H NMR spectroscopy and were found to depend essentially on the
通过与在氮原子上的R基团具有代表性尺寸的三个N,N-二烷基氨基亚磺酰氯2反应,已将几种取代的仲炔丙醇(Ia-f)转化为相应的非对映异构烯丙亚磺酰胺3a-n和3 'aj,lm。它们的比率已经通过1 H NMR光谱法确定,并且发现其比率基本上取决于起始材料的R 1和R 2基团的大小。一种纯非对映异构体3m的立体化学已通过单晶X射线分析确定。
Diastereo- and enantioselective synthesis of allenylcarbinols through SE2' addition of transient nonracemic propargylic stannanes to aldehydes.
作者:James A. Marshall、Richard H. Yu、Jolyon F. Perkins
DOI:10.1021/jo00122a040
日期:1995.9
The nonracemic allenylstannane 1c was prepared by S(N)2' displacement of mesylate 8 with Bu(3)-SnLi-CuBr . SMe(2). Treatment of this stannane with BuSnCl(3) followed by addition of isobutyraldehyde at -40 degrees C afforded the syn allenylcarbinol 4c in nearly 80% yield, The nonracemic aldehydes (S)- and (R)-16 were similarly converted to the adducts 17 and 18 in high yield with good to excellent diastereoselectivity. Best results were obtained when hexane was employed as the solvent, A reaction pathway is proposed to account for the steric preference of these additions, The allenylcarbinols were converted stereospecifically to the cis-2,5-dihydrofurans 23-25 upon treatment with catalytic AgNO3 in acetone.
Substituted 4-(1′,2′-alkadienesulphinyl)-morpholines; preparation and hydrolytic desulphinylation into the corresponding alkynes
作者:Jean-Bernard Baudin、Sylvestre A. Julia、Yuan Wang
DOI:10.1016/s0040-4039(01)80555-4
日期:1989.1
Diastereoselectivity in the [2,3]-sigmatropic rearrangement of substituted allylic N,N-dialkylamidosulfoxylates. X-ray molecular structure of [(1′) S*, (S)S*]-(2′E)-4-[[3′-(4″-bromophenyl)-1′-methyl-2′-propenyl]sulfinyl]-morpholine
作者:Jean-Bernard Baudin、Itka Bkouche-Waksman、Georges Hareau、Sylvestre A. Julia、Robert Lorne、Claudine Pascard
DOI:10.1016/s0040-4020(01)82318-8
日期:1991.8
By the reaction with three N,N-dialkylamidosulfenyl chlorides 2 bearing representative sizes for the R groups on the nitrogen atom, several substituted secondary E or Z allylic alcohols (1a-h) have been converted into the corresponding pairs of diastereoisomeric allylic sulfinamides (3+-3′a-v), whose ratios have been determined by 1H NMR spectroscopy. Five cases of entirely diastereoselective [2,3]-sigmatropic
通过与三个N,N-二烷基酰胺基亚磺酰氯2(在氮原子上具有代表性的R基团)反应,一些取代的仲E或Z烯丙基醇(1a-h)已转化为相应的非对映异构烯丙基亚磺酰胺(3 + -3'av),其比例已通过1 H NMR光谱测定。已经观察到五例完全非对映选择性[2,3]-σ重排的情况。