Thioallyl anions

The thioallyl anion from (132) reacts with cyclopentadiene oxide (133) in THF at -78°C to give (134 R1=2-PyrS,R2,R =bond) (62 ) which was transformed into the allyl alcohol (134 R R bond, R =0H) (713S) as part of a prostacyclin synthesis. ... 

Methylthioallyl anion undergoes op-1,4-addition to enones in the presence of HMPA, while 1,2-addition occurs in its absence. The anion (53) derived from 2H-thiopyran (52) by abstraction of the 6-proton (this is the anion that is favoured under conditions of thermodynamic control) has been found to undergo alkylation with Bu Br. Rather than involving an unprecedented S 2 attack at Bu Br, the reaction may involve a one-electron-transfer process. Other studies on the reactions of anions related to (53) have been published. Thioallylic anions have been employed in syntheses of 2-vinylthian, l,l-disilylalk-2-enes, and the natural products mokupalide, manicone, ( )-laurencin, and (6Z)-hedycaryol isomers, amongst other compounds. ... 

The thioallylic anions (7, E or Z), which are derived from the corresponding E- or Z-thiocarbamates by lithiation, add stereospecifically to benzaldehyde to give the corresponding vinylcarbamates, e.g. (8) from Z-(7). The chiral enolates... 

Thioallyl and Related Anions. Alkylation of thioallyl anions, often termed Biellmann alkylation, represents a useful method for forming new C—C bonds, as illustrated by the synthesis of dendrolasin (49), which is a furanoterpene... 

The regioselectivity of alkylation and carbonyl addition of various thioallyl anions has been examined, particularly with regard to chelation and ion-pairing effects. Thus, Biellmann and co-workers have found that thioallyl-lithium (50), in the presence of [2,2,2]cryptate, adds to acetone exclusively from the... 

The regioselectivity of alkylation has also been studied with cyclic thioallyl anions, with thioallyl-copper systems which involve 5n2 reactions, and with the dianion of prop-2-enethiol (5 ). > The products of addition of aldehyde at the a-position of (50) have been converted into cyclopropane... 

Thioallyl anions such as (55) may participate in vis + ttAs cycloadditions as the 47t component. The [2,3]-sigmatropic rearrangements of anions of... 

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