5.5
[1]. Shatrughan P Shahi, et al. A mild method for the preparation of gamma-hydroxy-alpha,beta-acetylenic esters. Angew Chem Int Ed Engl. 24 May ;4(19):2525-7.
H2-H15-H19-H5
P261-P264-P27-P271-P28-P2+P52-P4+P4-P5+P51+P8-P-P62+P64-P4+P2-P45-P51
GHS7