The fi
rst o
rganocatalytic enantioselective di
rect
rs/alpha.gif" BORDER=0>-alkynylation of
rs/beta2.gif" BORDER=0 ALIGN="middle">-ketoeste
rs and 3-acyl oxindolesis desc
ribed. It is demonst
rated that activated
rs/beta2.gif" BORDER=0 ALIGN="middle">-halo-alkynes unde
rgo nucleophilic acetylenic substitutioncatalyzed by chi
ral phase-t
ransfe
r compounds to affo
rd the alkynylated p
roducts in high yields and excellentenantioselectivities. The potential of the
reaction is fi
rst demonst
rated fo
r va
rious alkynylating
reagentshaving chlo
ride and b
romide as the leaving g
roups and substituents such as allyl and alkyl este
rs, amides,ketones, and sulfones. These
reactions p
roceed with 74-99% yield and 88-97% ee. Then the scope innucleophile is demonst
rated fo
r a la
rge numbe
r of cyclic
rs/beta2.gif" BORDER=0 ALIGN="middle">-ketoeste
rs with va
rious
ring-sizes and fo
r oxindolesas well. The co
rresponding optically active p
roducts a
re fo
rmed in high yields and with enantioselectivitiesup to 98% ee. The p
rocedu
re allows fo
r the ste
reocont
rolled attachment of an ethynyl unit in the
rs/alpha.gif" BORDER=0>-positionto the ca
rbonyl compound by facile
removal of the activating g
roup, and this has been demonst
rated fo
r anumbe
r of the optically active allyl este
rs. Fu
rthe
rmo
re, the synthesis of optically active 1,4-enynes is alsoshown. The isolation and cha
racte
rization by X-
ray analysis of the catalyst with
p-nit
rophenolate as thecounte
rion allowed us to p
ropose a model of the catalyst-subst
rate inte
rmediate which might account fo
rthe obse
rved enantioselectivity of the o
rganocatalytic enantioselective
rs/alpha.gif" BORDER=0>-alkynylation
reaction. Fu
rthe
rmo
re,it is suggested that this inte
rmediate is also the
reactive species fo
r a numbe
r of othe
r elect
rophiles addingto
rs/beta2.gif" BORDER=0 ALIGN="middle">-ketoeste
rs giving enantioselectivities in the
range of 90-98% ee.