Lactams Copper chloride

When either an alcohol or an amine function is present in the alkene, the possibility for lactone or lactam formation exists. Cobalt or rhodium catalysts convert 2,2-dimethyl-3-buten-l-ol to 2,3,3-trimethyl- y-butyrolactone, with minor amounts of the 8-lactone being formed (equation 51).2 In this case, isomerization of the double bond is not possible. The reaction of allyl alcohols catalyzed by cobalt or rhodium is carried out under reaction conditions that are severe, so isomerization to propanal occurs rapidly. Running the reaction in acetonitrile provides a 60% yield of lactone, while a rhodium carbonyl catalyst in the presence of an amine gives butane-1,4-diol in 60-70% (equation 52).8 A mild method of converting allyl and homoallyl alcohols to lactones utilizes the palladium chloride/copper chloride catalyst system (Table 6).79,82 83... 

The Kinugasa reaction has been used as well for the asymmetric synthesis of P-lactams 25 via cycloaddition between chiral oxazolidinyl propynes and nitrones, in the presence of copper chloride <02TL5499>. 

In combination with the incremental advances concerning reaction conditions in recent years, especially for low-pressure carbonylations, there is a trend toward increasing use of this chemistry to synthesize advanced building blocks. In this respect carboxylation of alkenes with an appropriate alcohol or amine function leads to the formation of lactones or lactams. Thus, cobalt, rhodium, or palladium chloride/copper chloride catalysts convert allyl and homoallyl alcohols or amines to the corresponding butyrolactones or butyrolactams, respectively [15]. 

Treatment of oxaziridine 294 with copper(l) triphenylphosphine chloride afforded cleanly lactam 295 in 82% yield (Scheme 8) <1998TL5853, 2006S1981>. The lactam presumably results from the closure of an intermediate aminyl... 

Laccaic acid, 537 a-Lactams, 756, 924, 8-Lactams, 234 Lactose, 61,1171 A .8( )-Lanostadiene, 151 A -Lanostene derivative, 468 Lanosterol, 916 5o-Lanosteryl 3 3-formate, 599 Laudanosine, 1106 methochloride, 1106 Laurie acid, 648-649, 666,1263, 1271 Laurone, 1199 Lauroyl azide,1041,1042 Lauroyl chloride, 1041, 1042,1199 Lauryl alcohol, 453 Lauryl bromide, 453, 1165 Lauryl mercaptan, 1165 Lazier catalyst, see Copper chromite Lead acetate trihydrate, 433,532-533 Lead dioxide, 215, 347, 409, 533-536, 537, 543, 554... 

The synthesis of unnatural (+)-mesembrine (387) through the asymmetric synthesis of methyl (i )-l-[(3,4-dimethoxy)phenyl]-4-oxocyclohex-2-enyl acetate (390) by cycloaddition of enantiomerically pure vinyl sulfoxide with dichloroketene has been performed 189) (Scheme 43). Vinyl sulfoxide 388 [prepared by conjugate addition of enantiopure acetylenic sulfoxide with (3,4-dimethoxy)phenylcopper] reacted with trichloroacetyl chloride in the presence of freshly prepared zinc-copper couple in THF at 0°C to produce a mixture of mono- and dichloro lactones 389. Reduction of 389 with zinc in acetic acid followed by cyclization and methylation afforded methyl IR-[(3,4-dimethoxy)phenyl]-4-oxocyclohex-2-enyl acetate (390), treatment of which with methylamine brought about amidation and concomitant intramolecular Michael addition to provide 2-oxo-mesembrine (391). Successively, 391 was transformed to (+)-mesembrine (387) in 79% yield (three steps ketalization of an oxo group, reduction of lactam, and deketali-zation)(/S9). 

It has been known for some time that ligands 27, 35, and 36 can be used for direct synthesis of oxidized Cu(I) chloride solutions which are useful catalysts for oxidative coupling processes (26,27). Amide and lactam ligands contain the nitrogen atoms of amines (which generally promote Cu(I) oxidation, see above) and also serve as crude models for the peptide link of proteins, which is the general environment of copper found in oxidases (28). 

Syntheses of ( )-canadine, ( )-thalictricavine, ( )-corydaline, and berlambine have been achieved from dimethoxyhomophthalic anhydride (88). The anhydride reacts with hydrastinine (87 R R = CH2) and its dimethoxy-analogue (87 R = r2 = Me) to give the lactam acids (89 R R CH2) and (89 R = R = Me) the methyl esters of which, on reduction with lithium aluminium hydride, yield the alcohols (90 R R = CH2, R = CH2OH) and (90 R = R = Me, R = CH2OH). The conversion of these alcohols into their methanesulphonyl esters, followed by reduction with sodium borohydride, then affords ( )-thalic-tricavine(90 R R = CHa,R = Me) and( )-corydaline(90 R = R = R = Me). Oxidation of the lactam acid (89 R R = CH2) with lead tetra-acetate and copper(ii) acetate in acetic acid and dimethylformamide gives the unsaturated lactam berlambine (91), which can be reduced by lithium aluminium hydride in the presence of aluminium chloride to ( )-canadine (90 R R = CH2, R" = H). ... 

Introduction of the ethylidene moiety was next achieved via a two-step sequence consisting of an aldol reaction of lactam 126 with acetaldehyde, followed by dehydration employing N, N-dicyclohexylcarbodiimide (DCC) and copper(I) chloride in benzene at reflux (Scheme 8). Methanolysis of the lactam in indohne 127, followed by reduction with DIBAL—H, next furnished aUyl alcohol 128. Conversion to an aUyl halide then permitted a base-mediated cyclization to form the tertiary amine 129, a substrate containing the carbon skeleton ofvincorine (18). 

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