Q18 · CSIR-NET Chemistry, December 2014
Paper: CSIR-NET December 2014 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Easy
Under review — part of this question (a structure or an option) is not clear in the source scan. 4AB is checking it against the original book; the answer shown may change.
The products A and B in the following reaction sequence are 
(a)
B = 
B = (b)
B = 
B = (c)
(d)
Answer
Under review — not yet confirmed.
Answer: A
Explanation
TBAF removes the silyl group to give the indole-2,3-quinodimethane; N-acylation by the mixed anhydride gives the 2-aza-diene A, and heating triggers an intramolecular Diels–Alder onto the pendant alkene to build the tetracyclic lactam B (a).
Study loop for Reagents, Reaction Mechanisms & Named Reactions