Facioselectivity and Vectoselectivity - Reaction Paths - Quartets

The joint consideration of stereofacioselectivity and vectoselectivity for the 11 types of stereofaces (paired faces) leads to 12 facioselectivity-vectoselectivity modes - Aa, An, Na, Nn, 

In the said designations, the first letter - in upper case - indicates facioselectivity  

The second letter (in lower case) refers to vectoselectivity  

Quartets ql-q3 are stereofacioselective ql and q2 are vectoaselective, whereas quartet q3 is vectononselective. 

Quartets q4-q21 are stereofaciononselective. In this group of quartets, q5 is vectoaselective, q4 is vectononselective, q6-ql2 are vectostereoselective, ql3,ql5,ql7,ql9,q20 are vectoastereo-selective, and ql4,ql6,ql8 and q21 are vectononequiselective. 

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