Prediction of optical rotations of RCHXY molecules using the electron-withdrawing powers of the four groups. The numbers next to the groups are the σ_p constants.

X	Y
	–NH2	–OH	–OR	–OCOR	–Ph	–X
–NH2 or –NR2	n/a		—	—		—
–OH or –OR	See row 2-column 3	—	—	—	See row 4-column 3	—
–Ph			—		—	—
–COOR or –COOH
–CF3	—		—	—	—	—
–CN	—			—	—	—