Tropic acid ethyl ester

Scheme 4.40 DKR of primary alcohols derived from tropic acid ethyl ester with Shvo s catalyst.

In the same area, Atuu and Hossain have developed the DKR of a series of other primary alcohols derived from tropic acid ethyl ester. Indeed, these substrates led to the formation of the corresponding acetates in good yields and moderate to high enantioselectivities when submitted to a combination of lipase PS and Shvo s catalyst in the presence of isopropenyl acetate, as shown in Scheme 8.46. These products constituted precious precursors of... 

Troplc acid is found in nature as the acid moiety of the anticholinergic ester alkaloids hyoscyamine (Scheme 57.4) and scopolamine. These tropane alkaloids can be extracted from plants of the Solanaceae family. Once proven that racemic tropic acid ethyl ester rac-8, which bears a primary hydroxyl group, is enantioselectively acylated with vinyl acetate in the presence of Celite-supported PS lipase and that the product thus formed has the required S configuration, Hossain and Atuu attempted the enzymatic acylation... 

Atuu MR, Hossain MM. Dynamic kinetic resolution of racemic tropic acid ethyl ester and its derivatives. Tetrahedron Lett. 2007 48 3875-3878. 

Ethyl ester Methyl ester (-Tropic Acid... 

Nearly 40 years later, when additional amounts of tropic acid were sought, an alternative synthesis was developed by Muller. As shown in Scheme 13.3, when the ethyl ester of phenylacetic acid was allowed to condense with ethyl formate in ether and in the presence of sodium metal and the resulting condensation products was reduced with aluminum amalgam, the corresponding ethyl ester of tropic acid was isolated. Hydrolysis of the ester was accomplished (again) with barium hydroxide (Scheme 13.3). The question of stereochemistry was not addressed. 

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