Consider the following groups attached to a chiral carbon centre:

Question

Consider the following groups attached to a chiral carbon centre: What is the decreasing order of priority of above groups based on Cahn-Ingold-Prelog (CIP)- nomenclature?

Vimal Swarnkar · Accepted Answer

(a) 1 > 4 > 2 > 3. First atoms all C. Substituent sets: −C≡CH (C,C,C) highest. −CH=CH₂ (C,C,H) and −CH(CH₃)₂ (C,C,H) tie; go one step further: vinyl's duplicated C gives (C,H,H) vs isopropyl (H,H,H) → vinyl > isopropyl. −CH₂CH₃ (C,H,H) lowest. 1 > 4 > 2 > 3 → (a).

Answer

(b) 1 > 2 > 3 >4

Answer

(c) 2 > 1 > 4 > 3

Answer

(d) 4 > 1 > 3 > 2

Geo-Scientist Prelims 2020 Chemistry Q93: Consider the following groups attached to a chiral carbon centre:

QuestionStereochemistry / CIP rules