Yield:-

Reaction Conditions:

Stage #1: 1-tert-butyl 2-methyl 2-(prop-2-en-1-yl)pyrrolidine-1,2-dicarboxylatewith potassium hydroxide in ethanol;water; for 48 h;
Stage #2: with hydrogenchloride in ethanol;water; pH=3;

Steps:

Synthesis of Compound 36

Synthesis of Compound 36 To a solution of compound 35 in ethanol (30 mL) was added 2 equivalent of 4N KOH aqueous solution, and the mixture was stirred for 48 h. The reaction mixture was concentrated under reduced pressure, followed by addition of water (50 mL). The basic solution was acidified using HCl 2N to adjust the pH to 3. This was followed by the extraction of the reaction mixture with ethyl acetate (100 mL). The concentration of the organic phase and subsequent recrystallization from ethyl acetate/hexane mixture gave pure Boc-α-allylproline (36) (2.5 g).

References:

US2006/199853,2006,A1 Location in patent:Page/Page column 43