Asymmetric Synthesis of Substituted Homoallyl Alcohols, Halomethyl Tetrahydrofurans, and Chloro-amino Sulfones from Allyltitanium Sulfoximines and α-Hetero Aldehydes

Abstract

Asymmetric syntheses of the iodomethyl-substituted bicyclic tetrahydrofuran 22 and the chloro-amino sulfone 30 from the allylic sulfoximine 15 and the alpha-hetero aldehydes 2 and 23, respectively, are described. Further examples for the asymmetric synthesis of chloromethyl tetrahydrofurans and chloro-amino sulfones are given. The synthesis of 30 features as key step the stereoselective Cl-substitution of a hydroxy group under neighboring group participation by an aminosulfoxonium group which is converted to a sulfonyl group. [reaction: see text].

C-Glycosylation Reactions of Sulfur-Substituted Glycosyl Donors: Evidence against the Role of Neighboring-Group Participation

“…The use of neighboring-group participation to control stereochemistry has proven to be an effective strategy for a number of transformations. − Carbohydrate chemistry, in particular, has benefited from the application of anchimeric assistance in glycosylation reactions. , Sulfur-, , iodine-, , and acetoxy-substituted , glycosyl donors undergo highly trans-selective reactions, which have been postulated to involve nucleophilic ring-opening reactions (S N 2) of onium ion intermediates (Scheme ) . For example, Boons and co-workers recently demonstrated the utility of neighboring-group participation in their elegant method for the synthesis of α-glycosides .…”

Sulfoximine‐Based Modular Enantioselective Synthesis of Azaspirocycles Featuring Sulfoximine Displacement, Dianion Cycloalkylation, RCM and N‐Acyliminium Ion Formation

“…We have previously described the diastereoselective synthesis of further hydroxyalkyl‐substituted cycloalkenylsulfoximines of type III , which carry functional groups X 1 and X 2 and have five‐, six‐ and seven‐membered rings, from IV and aldehydes (see Figure S1 in the Supporting Information) 6,13. Therefore, various ring A +C * B building blocks of type III are available for the synthesis of Ia – c .…”

“…N ‐Methylsulfoximines, containing a methyl group, a primary or secondary alkyl group, or an allyl group at the S atom, readily undergo dealkylation under cleavage of the S–C bond upon treatment with haloformates 6d,13,22. Although most of the sulfoximines studied contained functional groups that were capable of exerting a neighbouring group effect in the displacement, some were devoid of such a group or contain one in a sterically disabling position (see Figure S2 in the Supporting Information).…”

Synthesis of chiral sulfoximines derived from 3-aminoquinazolinones and their catalysis of enantioselective diethylzinc addition to aldehydes

“…Sulfoximines are of considerable interest since they are substrates for conversion into biologically active molecules such as alkaloids [13][14][15][16][17][18][19] and amino acids. [20][21][22][23] Their chirality makes them potentially useful in stereoselective synthesis [24][25][26][27][28][29] and new synthetic applications are currently being developed.…”