Propargylic rearrangements functional group transformation

Marshall [117] prepared several enantiomericaUy pure aUenylstannanes 485 either by cuprate Sn2 displacement of propargylic mesylate 486 or via a Claisen-Johnson rearrangement from alcohol 483. After functional group transformations, correlation was achieved between the two series of compounds... 

The transformation of an allylic alcohol to an allylic halide (equation 5) or the reverse reaction normally leads to a mixture of isomers of direct and allylic substitution products. Only when tertiary allylic alcohols are employed or a rearrangement leads to extended conjugation of double bonds does a transposition of functionality occur predominantly While a number of procedures have been developed for the conversion of allylic alcohols to halides without rearrangement, there seems to be only one reaction where a cleanly rearranged product is obtainable in a substitution of a primary or secondary allylic (and propargylic) hydroxy group to a chloride, that is by thionyl chloride in ether, probably by a cyclic SNi process. The regioselectivity is worse in other solvents and is lost in the presence of a base. In accordance with the mechanism it is a syn facial substitution, as has been demonstrated in cyclic cases (equa-... 

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