EXPLORATION OF HIGH SYMMETRY DIRHODIUM CATALYSTS AND THE REACTION OF DONOR/ACCEPTOR CARBENOIDS WITH ALCOHOLS Public
Li, Zhanjie (2010)
Published
Abstract
Chiral dirhodium complex catalyzed decomposition of diazo compounds
results in a
wide range of useful and highly stereoselective transformations.
The symmetry of the
catalyst has been considered as an important factor in its ability
to induce
stereoselectivity. In the first chapter of this dissertation, a
series of highly symmetric
dirhodium complexes containing mono, di, and
tetra-binaphthylphosphate ligands were
synthesized. The influences of substituents at the 3.3'- and
4,4',6,6'- positions of the
binaphthyl scaffold on the complex's catalytic reactivity were
systematically studied. The
synthesis of chiral dirhodium carboxylate complexes containing
admantyl groups was
also briefly explored. Two of this type of complexes were
effectivly synthesized in very
short sequence from aryldiazoacetates and admantane.
The second chapter of this dissertation focused on the reaction
of donor/acceptor
carbenoids with alcohols. A novel tandem ylide
formation/[2,3]-sigmatropic
rearrangement between donor/acceptor carbenoids and allylic
alcohols or propargylic
alcohols was discovered and systematically studied.
α-Hydroxycarboxylate derivatives
containing one tertiary alcohol stereocenter were synthesized with
excellent
stereoselectivity (up to >97:3 dr and >99% ee), when
dirhodium tetraprolinate, Rh2( S-
DOSP)4, was used as catalyst. It was found that chirality of the
catalyst had dominant
effect on the configuration of the tertiary alcohol stereocenter in
the product, and the
chirality of the alcohols had domnant effect on the second
stereocenter generated in the
rearrangement. Donor/acceptor carbenoids had distinct advantage
than the conventional
acceptor and acceptor/acceptor carbenoid in favor of the
[2,3]-sigmatropic
rearrangement. A highly enantioselective [1,2]-Stevens
rearrangement between
donor/acceptor carbenoids and tertiary benzyl alcohol was also
briefly studied. α-
Hydroxycarboxylates containing two adjacent quaternary centers were
formed in 78-94%
ee.
Table of Contents
Chapter 1 Design and Synthesis of Highly Symmetric Chiral
Dirhodium(II) Complexes
for Carbenoid
Chemistry…………………………………………………………………1
1.1
Introduction………………………………………………………………………….1
1.1.1 Dirhodium
carboxylates………………………………………………………….4
1.1.1.1 Proline derived dirhodium
complexes………………………………………...4
1.1.1.2 Phthalimide derived dirhodium
complexes…………………………………...8
1.1.2 Dirhodium
carboxamidates………………………………….…………………..12
1.1.3 Dirhodium binaphthylphosphate
complexes…………………….....……………16
1.2 Results and
discussion…………………………..………………………….……....18
1.2.1 Synthesis of dirhodium binaphthylphosphate
complexes………………….........18
1.2.1.1 Dirhodium tetrabinaphthylphosphate complexes
(Rh2L4)………………..….20
1.2.1.2 Dirhodium complexes containing mixed ligands
(Rh2Ln(OAc)(4-n))………...25
1.2.2 Synthesis of dirhodium phosphinate
complex…………………………………..36
1.2.3 Synthesis of chiral dirhodium carboxylate
complexes………………………….40
1.3
Conclusion…………………………………………………………………………..45
1.4
Experimental………………………………………………………………..………46
1.4.1 General
information………………………………………………………..……46
1.4.2 Synthetic procedures and
characterization………………………………………47
References………………………………………………………………………………103
Chapter 2 Highly Enantioselective C-C Bond
Formation by Rhodium-Catalyzed
Tandem Ylide Formation/[2,3]-Sigmatropic Rearrangement between
Donor/Acceptor
Carbenoids and Allylic Alcohols/Propargylic
Alcohols…………………………….…110
2.1
Introduction……………………………………………………………………..…110
2.1.1 Intermolecular
cyclopropanation………………………………………………111
2.1.2 Intermolecular C-H
insertion………………………………………………….117
2.1.3 Ylide
formation……………………………………………………………...…122
2.2 Results and
discussion……………………………………………………...……..128
2.2.1 New
discovery…………………………………………………………...…….128
2.2.2 Tandem oxonium ylide formation/[2,3]-sigmatropic
rearrangement between
donor/acceptor carbenoids and allylic alcohols - generation of one
stereogenic
center……………………………………………………………………………..….131
2.2.2.1 Optimal reaction
conditions…………………………………………..…….133
2.2.2.2 Effect of allylic
alcohols………………………………………………..…..136
2.2.2.3 Effect of carbenoid
structure…………………………………………..……138
2.2.2.4 Effect of chiral alcohol
……………………………………………………..140
2.2.2.5 Reactions of styryldiazoacetate 7 with racemic allylic
alcohols……...……141
2.2.2.6 Other
features………………………………………………………...……..147
2.2.3 Tandem oxonium ylide formation/[2,3]-sigmatropic
rearrangement between
donor/acceptor carbenoids and allylic alcohols - generation of two
stereogenic
centers………………………………………………………………...………………151
2.2.3.1 Reactions with enantiomerically pure allylic
alcohols……………………..151
2.2.3.2 Rationale of the
stereoselectivity……………………………………..…….163
2.2.3.3 Further transformation
……………………………………………………167
2.2.4 Tandem oxonium ylide formation/[2,3]-sigmatropic
rearrangement between
donor/acceptor carbenoids and allylic alcohols containing silyl
group……………..171
2.2.5 Tandem oxonium ylide formation/[2,3]-sigmatropic
rearrangement between
donor/acceptor carbenoids and propargylic
alcohols………………………………..174
2.2.5.1 Reactions with achiral propargylic
alcohols………………………….……175
2.2.5.2 Reactions with chiral tertiary propargylic
alcohols……………….………..182
2.2.5.3 Reactions with chiral secondary propargylic
alcohols……………….…….186
2.2.5.4 Stereoselective cyclization of α-allenic
alcohols………………….………188
2.2.5.5 Rationale of the
stereoselectivity………………………………………..…189
2.2.6 Highly enantioselective intermolecular [1,2]-Stevens
rearrangement between
donor/acceptor carbenoids and tertiary
alcohols……………………………………..192
2.3
Conclusion………………………………………………………...………………197
2.4
Experimental………………………………………………………………………199
2.4.1 General
information……………………………………………………………199
2.4.2 Synthetic procedures and characterization for chapter
2.2.1
and
2.2.2……………………………………………………………………….……200
2.4.3 Synthetic procedures and characterization for chapter
2.2.3…………….…… 246
2.4.4 Synthetic procedures and characterization for chapter
2.2.4…………….…… 282
2.4.5 Synthetic procedures and characterization for chapter
2.2.5………….……… 289
2.4.6 Synthetic procedures and characterization for chapter
2.2.6………………… 343
References…………………………………………………………………………..…..350
Appendix Crystal Structure
Determination……………………………………………361
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