... of ethyl buta-2,3-dienoate with the chiral dehydroamino acid derivative (R)-3. 4 We now report here the full details of this synthesis and an ... Scheme 7 a. a Reagents: (i) Bu 3 P (10 mol %), PhH, RT, 16 h (87%); (ii) 1 N HCl, ether, 16 h, RT (95%); (iii) BnOCOCl, Na 2 CO 3 , 2 h, 0 ...