2- Lithiodithiane

These aspects have been investigated for a number of substituted benzyllithium systems—Q -(phenylthio)benzyllithium (3), a-phenyl-a-lithiodithiane (4) and a-trimethylsilyl... 

Other reactions of electron-poor aza-heterocycles that are suspected to involve a SET mechanism include 1-lithiodithiane with pyridine (73CL1307) and 1,8-naphthyridine (78ZC382), and LDA with pyridine (82JOC599). 

Analogous to the observations with pyridine, quinoline, and isoquinoline, 1,8-naphthyridine (490) was shown to produce a dimer 492 upon treatment with 1-lithiodithiane (73CL1307). Electron spin resonance... 

Acylation with Lithiodithianes 2.4.9J Miscellaneous Reactions of Dithioacetals... 

The reactim of 2-cyclohexenone with 2-lithiodithiane occurs in a 1,2-fashion to give the unsaturated hydroxy derivative, which, after rearrangement followed by deprotection, gives 3-hydroxy-1-cyclohex-enecarbaldehyde. ... 

Intramolecular addition of lithiodithiane to an acetal leads to the fnination of cyclic derivatives (equation 35). Carbonyl additions have been extended to the analogous imonium salts (R2C NR2), which furnish a-amino ketones. ... 

The reaction of 6-deoxy-6-iodo-l,2 3,4-di-0-isopropylidene-a-D-galactopyranose with 2-lithiodithiane yields an unsaturated open chain heptose derivative (equation 36). "... 

Reaction of lithiodithianes with acyl chlorides, esters or nitriles leads to the fOTination 1,2-dicarbonyl compounds in which one of the carbonyl groups is protected as the thioacetal. d76043j44 Optically active amino ketones of type (69) are inepared via acylation of dithiane with an oxazoline-protected (5)-serine methyl ester (Scheme 41). Optically active (5)-2-alkoxy-l-(l,3-dithian-2-yl)-l-propanones were prepaid by the reaction of the corresponding methyl (5)-lactate with 2-lithio-l,3-enantioselective synthesis of (-)-trachelanthic acid. Enantioselective synthesis of L-glyceraldehyde involves the acylation of a dithiane glycolic acid derivative followed by bikers yeast mediated reduction. ... 

E xides and oxetanes react readily with lithiodithiane to give derivatives of 3- or y-hydroxy aldehydes or ketones. The method has been used for the multistep synthesis of an inomycin fragment, thietane prostaglandin analogs, branched-chain nucleoside sugars, the southern hexahydrobenzctfu-ran unit avermectin, the anti-Gram-positive bacterial elaiphylin andsyn-l,3-polyols. ... 

Lithiodithiane is aminated by reaction with a vinyl azide, as shown in equation (38). ... 

Reaction of 2-lithiodithiane and 1,1-diethoxy-2,3-epoxypropane (4) gave the expected alcohol, which was acetylated to give (5). Hydrolysis by the new procedure gave 3-acetoxy-4,4-diethoxybutanal (6). Dehydroacetoxylation was then effected with DBU (1,5-diazabicyclo[5.4.0]undec-5-ene, 2, 101). 

Three total syntheses of racemic N-methylmaysenine (133b) have been described. The synthesis by Corey et al. [223] is based on the following key steps the formation of the C9-C10 bond by reaction of the corresponding 2-lithiodithiane with a dienal bearing the benzene nucleus (separation of diastereoisomers is required). Then, a dienoic acid was formed in order to carry out the lactamization of the resulting amino acid, which finally was submitted to carbamoylation and dithiane cleavage (Scheme 61). 

B.ii. Acyl Anion Equivalents. The most common umpolung equivalent is that for acyl anion 339, and dithianes 344 are the most common reagent used for this purpose. Dithiane 344 is prepared from an aldehyde, but ketones are also precursors (sec. 7.3.B.ii). Removal of the hydrogen adjacent to the sulfur requires a base such as n-butyllithium and the product is a-lithiodithiane (345). The acidity of this hydrogen is largely... 

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