Kulinkovich Reaction库林科维奇反应

-hydride

氢化

物

elimination

with

the

loss

of

ethane

to

yield

the

substituted

titanacyclopropane:

取代钛杂环丙烷中间体

The titanacyclopropane reacts with the ester as a 1,2-dicarbanion

双碳负

离子

equivalent to produce a cyclopropanol after a 2-fold alkylation2

倍

烷基化

:

Titanium(II) is reoxidized to titanium(IV) over the course of this addition

process.

The

last

intermediate

in

the

sequence

can

be

recognized

as

a

Ti(OR'')

4

species,

which

can

undergo

reaction

with

EtMgBr

similar

to

Ti(O

i

Pr)

4

.

Thus,

titanium(IV)

isopropoxide

can

be

used

in

catalytic

amounts:

The

production

of

ethene

has

been

attributed

to

a

side

reaction

of

the

titanacyclopropane with additional titanium(IV) isopropoxide to afford 2

equivalents

of

titanium(III)

isopropoxide

(Kulinkovich,

Synlett

2004

,

).

This

non-productive

side

reaction

reaches

a

maximum

as

the

ratio

of

titanium(IV)

isopropoxide

to

EtMgBr

approaches

a

stoichiometry

[ ,st

??

k

?

'

?

m

?

t r

?

]

of

1:1.

However,

this

sequence

can

be

useful

for

the

generation

of

low

valent

titanium

compounds

that

can

be

utilized

for

example inPinacol

频哪醇

Coupling Reactions.