Lithium Hydroxide → rac-(1R,2R)-2-(4-bromophenyl)cyclopropane-1-carboxylic acid

HRID 2246788Notes

Reaction equation

HRID 2246788 reaction equation
C(C1OC[C@H](C(C)(C)C)N=1)(C1OC[C@H](C(C)(C)C)N=1)(C)C.C(OC(=O)C=[N+]=[N-])C.[Br:30][C:31]1[CH:36]=[CH:35][C:34]([C@@H:37]2[CH2:39][C@H:38]2[C:40]([O:42]CC)=[O:41])=[CH:33][CH:32]=1.BrC1C=CC(C=C)=CC=1.[Li+].[OH-]>[O-]S(C(F)(F)F)(=O)=O.[Cu+]>[Br:30][C:31]1[CH:32]=[CH:33][C:34]([C@@H:37]2[CH2:39][C@H:38]2[C:40]([OH:42])=[O:41])=[CH:35][CH:36]=1

Participants

7

Reactant 5

HCID 3939Lithium HydroxideHCID 12192Ethyl diazoacetateHCID 162634-BromostyreneHCID 688208t-Bu-box, (S,S)-HCID 66578655ethyl (1R,2R)-2-(4-bromophenyl)cyclopropanecarboxylate

Product 1

HCID 12586658rac-(1R,2R)-2-(4-bromophenyl)cyclopropane-1-carboxylic acid

Reagents, catalysts & solvents 1

HCID 9813164Copper(I) trifluoromethanesulfonateCatalyst

Procedure

An enantioselective cyclopropanation analogous to a literature procedure (Evans et al. J. Am. Chem. Soc. 1991, 113, 726) using commercial 2,2′-isopropylidenebis[(4S)-4-tert-butyl-2-oxazoline] in conjunction with copper(I) triflate and ethyldiazoacetate was used to prepare optically active ethyl (1R,2R)-2-(4-bromophenyl)cyclopropanecarboxylate from 4-bromostyrene. The absolute configuration was assigned by analogy based on the sense of the optical rotation. Selective hydrolysis of the trans isomer with LiOH (1 equivalent based on the trans ester) from the mixture of cis and trans esters (that was obtained by the cyclopropanation procedure) gave the title compound.

Workup

  1. customwas obtained by the cyclopropanation procedure)

Sources & evidence

ORD record
ord-e30787f88e2c4b70825b81ae3d6ed137
Source dataset
uspto-grants-2010_03
Patent number
US07687524B2

Reaction notes

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