ISSN:0165-0513    

DOI:10.1002/recl.19831020901

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

Abstractγ,δ‐Unsaturated β‐oxo esters can be converted into their dianions6by reaction with 2 equivalents of lithium diisopropylamide (LDA). Reaction of these dianions with alkyl halides leads exclusively to mono‐γ‐alkylation and affords the unsaturated oxo esters9in good yields. Reaction with carbonyl compounds similarly affords the unsaturated δ‐hydroxy β‐oxo esters10.The regiospecificity of these reactions is discussed in relation to the structure of the dianio

ISSN:0165-0513    

DOI:10.1002/recl.19831020902

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19831020903

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe synthesis of sulfines4from a series of active methylene compounds is described. Deprotonation, followed by silylation, gives the trimethylsilyl compounds2.Subsequent deprotonation to α‐silyl carbanions and treatment with an excess of sulfur dioxide leads to the formation of sulfines4, usually in good yields. The experimental conditions of this alkylidenation of sulfur dioxide, using the modifiedPetersonolefination, are discussed in detail. Hydrolytically sensitive sulfines can be prepared by using a dry work‐up procedure. These sulfines can also be trapped with 2,3‐dimethyl‐1,3‐butadiene to give dihydropyranS‐oxides5.Reaction of the α‐silyl carbanions with some sulfines leads to alkenes9, probably through the intermediacy of thioc

ISSN:0165-0513    

DOI:10.1002/recl.19831020904

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

Abstract1,3‐Dicarbonyl compounds and hydroxybenzenes condense under the influence of acid with ω‐hydroxylactams1–7in an intermolecular process, thereby affording ω‐alkylated lactams8–13.The reactive intermediate in the carbon‐carbon bond forming step is a cyclicN‐acyliminium ion. The intramolecular variant affords keto ester19.Upon activation of the ω‐hydroxylactam as a hexafluoroisopropoxy ester, condensations with cyanide in aprotic polar solvents under neutral conditio

ISSN:0165-0513    

DOI:10.1002/recl.19831020905

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractActive methylene compounds such as methyl ketones, 1,3‐dicarbonyl systems and nitromethane condense under the influence of base with ω‐hydroxylactams, thereby forming α‐alkylated nitrogen heterocycles. The ease of alkylation is determined by the position of a tautomeric equilibrium between ω‐hydroxylactam and the open‐chain amide‐aldehyde, which is dependent upon the type ofN‐substituent and upon the lactam ring size. Some applications for the products obtain

ISSN:0165-0513    

DOI:10.1002/recl.19831020906

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIn the presence of base thet‐butyldimethylsilyl (TBDMS) protective group is able to migrate between trans‐diaxial hydroxyl functions of carbohydra

ISSN:0165-0513    

DOI:10.1002/recl.19831020907

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCationic surfactants enhance the catalytic activity of imidazole containing polymers of isocyanides in the hydrolysis of activated esters.

ISSN:0165-0513    

DOI:10.1002/recl.19831020908

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractA cationic surfactant enhances the enantioselectivity of imidazole containing polymers of isocyanides in the hydrolysis of amino acid 4‐nitro‐phenyl est

ISSN:0165-0513    

DOI:10.1002/recl.19831020909

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY