Enantiopure acyclic (E)‐ and (Z)‐configured allylic sulfoximines have been synthesized from N,S‐dimethyl‐S‐phenylsulfoximine and aldehydes by the addition− elimination−isomerization route through the intermediate generation of the corresponding (E)‐configured vinylic sulfoximines. Isomerization of the vinylic sulfoximines with DBU preferentially afforded the corresponding (Z)‐configured allylic sulfoximines, which were subsequently isomerized by DBU to preferentially yield the (E)‐isomers. Titanation of lithiated (E)‐configured allylic sulfoximines with ClTi(OiPr)3 furnished the corresponding bis(2‐alkenyl)diisopropyloxytitanium(IV) complexes, which reacted with aldehydes in the presence of ClTi(OiPr)3 with high regio‐ and diastereoselectivities at the γ‐position to give the corresponding (Z)‐anti‐configured δ‐N‐methylsulfonimidoyl‐substituted homoallylic alcohols in good yields. In the absence of ClTi(OiPr)3 at low temperatures, only one allylic moiety of the bis(alkenyl)diisopropyloxytitanium complex is transferred to the aldehyde. In this way, a cyclic lithiated allylic sulfoximine has been converted with high regio‐ and diastereoselectivity to the corresponding homoallylic alcohols bearing a vinylic sulfonimidoyl group. Titanation of lithiated (E)‐ and (Z)‐configured allylic sulfoximines with ClTi(NEt2)3 afforded the corresponding mono(2‐alkenyl)tris(diethylamino)titanium(IV) complexes, which reacted with aldehydes with moderate to high regioselectivities and high diastereoselectivities preferentially at the α‐position to give the corresponding syn‐configured β‐N‐methylsulfonimidoyl‐substituted homoallylic alcohols along with the (Z)‐anti‐configured δ‐N‐methylsulfonimidoyl‐substituted homoallylic alcohols in good yields. In this way, the cyclic lithiated allylic sulfoximine was converted with high regio‐ and diastereoselectivity to the corresponding isomeric homoallylic alcohols bearing an allylic sulfonimidoyl group. In the case of mono(alkenyl)tris(diethylamino)titanium(IV) complexes, the regioselectivity of their reactions with aldehydes has been found to depend on the size of the substituent at the CC double bond and the aldehyde, as well as on the configuration of the double bond. Reaction of racemic lithiated N‐methyl‐S‐(3,3‐diphenyl‐2‐propenyl)‐S‐phenylsulfoximine with ClTi(OiPr)3 afforded the corresponding bis(alkenyl)diisopropyloxytitanium(IV) complex. X‐ray structure analysis revealed a distorted octahedral cis,cis,cis‐configured bis(2‐alkenyl)diisopropyloxytitanium(IV) complex, in which the allylic moieties are coordinated in a bidentate fashion through C‐α and the N atom to the Ti atom, both having the relative configuration RSSC. In solution, the titanium complex shows fluxional behavior, which is characterized by topomerization of the isopropyloxy groups and allylic moieties. The exchange of the latter occurs with retention of the configuration at C‐α.

A new method for the asymmetric synthesis of anti-configured homopropargylic alcohols 1 is described, which features the addition of chiral sulfonimidoyl substituted bis(allyl)titanium complexes 3 to aldehydes, the methylation of sulfonimidoyl substituted homoallylic alcohols 2 at the N-atom, and the elimination of alkenyl (dimethylamino)sulfoxonium salts 7 with LiN(H)tBu. The reaction of isopropyl, cyclohexyl, and methyl substituted allylic titanium complexes 3a-c with benzaldehyde, p-bromobenzaldehyde, p-chlorobenzaldehyde, p-methoxybenzaldehyde, (E)-3-phenylpropenal, and phenylpropynal afforded with high regio- and diastereoselectivities the anti-configured sulfonimidoyl substituted homoallylic alcohols 2a-j, respectively. Only one allylic unit of the titanium complexes 3a-c was transferred in the case of unsaturated aldehydes, and the starting allylic sulfoximines 2a-g were recovered in approximately 50% yield. The methylation of the silyl protected alkenyl sulfoximines 6a-j with Me(3)OBF(4) gave in practically quantitative yields the (dimethylamino)sulfoxonium salts 7a-j, respectively. Salts 7a-e, 7g, 7h, and 7j delivered upon treatment with 2 equiv of LiN(H)tBu the enantio- and diastereomerically pure saturated and unsaturated alkynes 9a-e, 9g, 9h, and 9j, respectively, in high yields. Besides the alkynes the sulfinamide 8 (96% ee) was isolated. Aminosulfoxonium salts 9f and 9i, which carry a CC triple bond, also suffered an elimination under these conditions but did not yield the corresponding diynes. Elimination of salts 7a-e, 7g, 7h, and 7j proceeds most likely through deprotonation at the alpha-position with formation of the novel alkylidenecarbene aminosulfoxonium ylides 19a-e, 19g, 19h, and 19j, respectively. The ylides 19a-e, 19g, 19h, and 19j presumably eliminate sulfinamide 8 with generation of the chiral nonracemic (beta-siloxyalkylidene)carbenes 20a-e, 20g, 20h, and 20j, which suffer a 1,2-H-shift with formation of alkynes 9. Support for the formation of the putative alkylidenecarbenes 20 as intermediates comes from the elimination of the beta-methyl substituted aminosulfoxonium salt 24, which delivered the enantio- and diastereomerically pure 2,3-dihydrofuran derivative 28 upon treatment with LiN(H)tBu in high yield. Here, the putative (beta-siloxyalkylidene)carbene 26 suffers a 1,5-O,Si bond insertion rather than a 1,2-Me shift. Methylation of the alkenyl sulfoximine 6a at the alpha-position with formation of 13 was achieved through deprotonation of the former with formation of the alpha-lithioalkenyl sulfoximine 11a and its treatment MeI. Reaction of the alpha-methylated alkenyl aminosulfoxonium salt 14a with LiNiPr(2) at low temperatures gave the enantio- and diastereomerically pure anti-configured homoallenylic alcohol derivative 15, while reaction of the salt with LiNiPr(2) or LiN(H)tBu at higher temperatures afforded the enantio- and diastereomerically pure nonterminal homopropargylic alcohol derivative 17. Deprotonation of the alkenyl (dimethylamino)sulfoxonium salts 7a and 7b with nBuLi ...

In this article, the cross-coupling reaction( CCR) of exocyclic, axially chiral, and acyclic alkenyl (N-methyl)sulfoximines with alkyl-and arylzincs is described . The CCR generally requires dual Ni catalysis and MgBr 2 promotion, which is effective in diethyl ether but not in THF.N MR spectroscopy revealedacomplexation of alkenyl sulfoximines by MgBr 2 in diethyle ther,w hichs uggestsa na cceleration of the oxidative addition through nucleofugal activation.T he CCR of alkenyl sulfoximinesg enerally proceedsi nt he presence of Ni(dppp)Cl 2 as ap recatalyst and MgBr 2 with alkyl-and arylzincs with ah igh degree of stereoretention at the Ca nd the Sa tom. CCR of axially chirala lkenyl sulfoximinesw ith Ni(PPh 3 ) 2 Cl 2 as ap recatalyst and ZnPh 2 does not require salt promotion and is stereoretentive.T he reactionw ith Zn(CH 2 SiMe 3 ) 2 ,h owever,d emands salt promotion and is not stereoretentive. CCR of axially chiral a-methylated alkenyl sulfoximines affordedp ersubstituted axiallyc hiral alkenes with high selectivity.A lkenyl (N-triflyl)sulfoximines engage in as tereoretentive CCR with Grignard reagents and Ni(PPh 3 ) 2 Cl 2 .Ni-Catalyzed and MgBr 2 -promoted CCR of E-configured acyclica lkenyl sulfoximinesa nd aminosulfoxonium salts with ZnPh 2 andZ n(CH 2 SiMe 3 ) 2 is stereoretentivew ith Ni(dppp)Cl 2 and Ni(PPh 3 ) 2 Cl 2 .C CRs of acyclica lkenyls ulfoximinesa nd alkenyl aminosulfoxonium salts, carrying am ethyl groupa tt he a position, take ad ifferent course andg ive alkenyls ulfinamidesu nder stereoretention at the Sa nd C atom.C CR of acyclic, exocyclic, and axially chiral alkenyl sulfoximines has been successfully applied to the stereoselective synthesis of homoallylic alcohols, exocyclic alkenes, and axiallyc hiral alkenes, respectively.

Alcohols Alcohols Q 0230Asymmetric Synthesis of anti-Homopropargylic Alcohols from Aldehydes and Chiral Sulfonimidoyl Substituted Bis(allyl)titanium Complexes Through Generation and Elimination of Novel Chiral Alkylidenecarbene (Dimethylamino)sulfoxonium Ylides. -This offers a new and general method to prepare anti-homopropargylic alcohols. Coupling of aldehydes with chiral sulfonimidoyl titanium complexes generated from the sulfimines (I) proceeds with excellent regio-and stereoselectivity. Transformation of sulfoxonium salts of type (VII) into alkynes proceeds via formation of novel chiral sulfoxonium ylides like (X) which is confirmed by isolation of the salt (XII) after trapping with MeI and preparation of the dihydrofuran (XVI) from the salt (XV). Interestingly, salts containing a β-H atom undergo 1,2-shift to alkynes, whereas β-dialkylated salts undergo intramolecular ring closure. This intramolecular ring closure offers a new route to chiral dihydrofurans, which are of synthetic interest. Starting from α-methylated salts such as (XII) chiral homopropargylic alcohols with an internal triple bond and homoallenic alcohols are available. -(REDDY, L. R.; GAIS*, H.-J.; WOO, C.-W.; RAABE, G.; J.