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Catalytic asymmetric organozinc reac...

Chen, Young K.

Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities.
Author:	Chen, Young K.
Description:	276 p.
Notes:	Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2933.
Notes:	Supervisor: Patrick J. Walsh.
Contained By:	Dissertation Abstracts International65-06B.
Subject:	Chemistry, Organic.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3137992
ISBN:	0496851624

Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities.
Chen, Young K.

Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities. - 276 p.

Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2933.

Thesis (Ph.D.)--University of Pennsylvania, 2004.

*Please refer to dissertation for diagrams.

ISBN: 0496851624Subjects--Topical Terms:

193634
Chemistry, Organic.

Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities.
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100 0 $a Chen, Young K. $3 227931
245 1 0 $a Catalytic asymmetric organozinc reactions: Mechanisms and synthetic utilities.
300 $a 276 p.
500 $a Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2933.
500 $a Supervisor: Patrick J. Walsh.
502 $a Thesis (Ph.D.)--University of Pennsylvania, 2004.
520 # $a *Please refer to dissertation for diagrams.
520 # $a In chapter 1, we present a nonlinear effects study using Nugent's beta-amino alcohol ligand (MIB). We found that with 4 mol% of MIB of 10% ee will effectively catalyze Et2Zn additions to benzaldehyde to give the resulting product of 89% ee. Under the same conditions, p-methoxybenzaldehyde afforded 95% ee and m-trifluoromethylbenzaldehyde provided 62% ee. All three substrates gave 98% ee when enantiopure MIB was used. This is the first example of the substrate dependency of nonlinear effects. The results in this study are inconsistent with prediction based on a model proposed by Noyori.*
520 # $a In chapter 2, we utilized MIB in a highly enantioselective and catalytic alkenylation of aldehydes that led to allylic alcohols in high enantio-purity. The resultant allylic alcohols are then transformed to the allylic amines via Overman's [3,3]-sigmatropic rearrangement of imidates. Oxidative cleavage of the allylic amines furnishes the amino acids derivatives in good yields and excellent ee's.*
520 # $a In chapter 4, a new one-pot, multicomponent coupling reaction that allows easy access to (Z)-trisubstituted allylic alcohols is outlined. Our strategy is based on E to Z isomerization of the 1-bromo-1-dialkylvinylborane upon reaction with dialkylzinc reagents, and subsequent transmetallation to give (Z)-trisubstituted vinylzinc species. In situ trapping of the reactive vinylzinc intermediates with aldehydes furnished a series of (Z)-trisubstituted allylic alcohols. This method represents a viable alternative to the Still-Gennari modification of the HWE olefination reaction, and it has the advantage that it allows coupling of larger fragments.*
520 # $a In this chapter, we present the first catalytic asymmetric two-carbon homologation of aldehydes based on an enantioselective synthesis of hydroxy enolethers followed by hydrolysis to the beta-hydroxy aldehydes. A catalytic variant of the hydrolysis is currently under development.*
590 $a School code: 0175.
650 # 0 $a Chemistry, Organic. $3 193634
690 $a 0490
710 0 # $a University of Pennsylvania. $3 212781
773 0 # $g 65-06B. $t Dissertation Abstracts International
790 $a 0175
790 1 0 $a Walsh, Patrick J., $e advisor
791 $a Ph.D.
792 $a 2004
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