The cation which is the least likely to be an intermediate in the following reaction is
Cyclopropanols are protonated readily on the strained ring, and the resulting cations undergo cyclopropylcarbinyl-to-cyclobutyl ring expansion (a semipinacol-type shift) to relieve strain.
Step 1 — Protonation of one cyclopropane ring opens it to an ethyl group, giving the hydroxy-stabilised carbocation on the carbinol carbon; this is the open-chain cation attached to the 1-hydroxycyclopropyl group, and its resonance form is the protonated ketone (O-protonated carbonyl).
Step 2 — The neighbouring 1-hydroxycyclopropyl group expands: a ring C–C bond migrates to the cationic carbon, producing the cyclobutyl cation that carries OH on the cationic carbon and OH plus ethyl on the adjacent quaternary carbon.
Step 3 — Loss of a proton from that hydroxy-substituted cation (an oxocarbenium ion) gives 2-ethyl-2-hydroxycyclobutanone. The spiro cation, in which a cyclobutyl cation still bears an intact cyclopropane, would require ionisation of a cyclopropanol C–O bond to a very unstable cyclopropyl cation before any ring opening; it also cannot lead to the ethyl-substituted product, so it is not on the pathway.
the spiro cyclopropane cyclobutyl hydroxy cation option is correct.
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Important Questions from Mixed Topic (MH-SET)
.................... is a client server application that identifies each host on the internet with a unique user-friendly name.
Every OS has a ................ or .......... which primarily resides in the main memory of the computer to perform some of the basic functions of the OS.
(i) Kernel
(ii) Interface
(iii) Nucleus
(iv) Compiler
Codes:
Which of the following are referred to as low level language?
(i) Machine language
(ii) Assembly language
(iii) High level language
(iv) Natural language
Codes:
Match the following:
List I List II (a) New York Public Library (i) Shelv AR (b) Miami University Augmented Research Group (ii) Smart library (c) Oula University Library (iii) Wolf Walk (d) North Carolina State University (iv) Find the future Codes:
Which part of the QR code represents the encoded data?
