The fir
st or
ganocatalytic enantio
selective direct
ge
s/
gifchar
s/alpha.
gif" BORDER=0>-alkynylation of
ge
s/
gifchar
s/beta2.
gif" BORDER=0 ALIGN="middle">-ketoe
ster
s and 3-acyl oxindole
si
s de
scribed. It i
s demon
strated that activated
ge
s/
gifchar
s/beta2.
gif" BORDER=0 ALIGN="middle">-halo-alkyne
s under
go nucleophilic acetylenic
sub
stitutioncatalyzed by chiral pha
se-tran
sfer compound
s to afford the alkynylated product
s in hi
gh yield
s and excellentenantio
selectivitie
s. The potential of the reaction i
s fir
st demon
strated for variou
s alkynylatin
g rea
gent
shavin
g chloride and bromide a
s the leavin
g group
s and
sub
stituent
s such a
s allyl and alkyl e
ster
s, amide
s,ketone
s, and
sulfone
s. The
se reaction
s proceed with 74-99% yield and 88-97% ee. Then the
scope innucleophile i
s demon
strated for a lar
ge number of cyclic
ge
s/
gifchar
s/beta2.
gif" BORDER=0 ALIGN="middle">-ketoe
ster
s with variou
s rin
g-
size
s and for oxindole
sa
s well. The corre
spondin
g optically active product
s are formed in hi
gh yield
s and with enantio
selectivitie
sup to 98% ee. The procedure allow
s for the
stereocontrolled attachment of an ethynyl unit in the
ge
s/
gifchar
s/alpha.
gif" BORDER=0>-po
sitionto the carbonyl compound by facile removal of the activatin
g group, and thi
s ha
s been demon
strated for anumber of the optically active allyl e
ster
s. Furthermore, the
synthe
si
s of optically active 1,4-enyne
s i
s al
so
shown. The i
solation and characterization by X-ray analy
si
s of the cataly
st with
p-nitrophenolate a
s thecounterion allowed u
s to propo
se a model of the cataly
st-
sub
strate intermediate which mi
ght account forthe ob
served enantio
selectivity of the or
ganocatalytic enantio
selective
ge
s/
gifchar
s/alpha.
gif" BORDER=0>-alkynylation reaction. Furthermore,it i
s su
gge
sted that thi
s intermediate i
s al
so the reactive
specie
s for a number of other electrophile
s addin
gto
ge
s/
gifchar
s/beta2.
gif" BORDER=0 ALIGN="middle">-ketoe
ster
s givin
g enantio
selectivitie
s in the ran
ge of 90-98% ee.