Question

for the first picture i need to find out what the 2nd reaction is (name of reaction). I have it as alpha alkylation but i’m not sure if thats correct. I am unsure because while LDA is adding the alkyl halide it is also adding an ester group along with it so I did not know if that was possible with the alpha allylation.

In the second picture i need to know what the name of the reaction the H+ is causing. i didnt know if it was acid catalyzed dehydration. In addion, what is the name of the reaction that caused the circled ring to form (with the oxygen). Thank you for any help.

in 66% yieid over two steps (Scheme 2). Scheme 2. Preparation of Intermediate 13 OH 2) LDAV 9 (B) ~ 55% and Scheme 1. Neovibsanin H (1), Neovibsanin 1 (2), 2-0-Methylneovibsanin H (3), and 2-0-Methylneovibsanin I (4) Proposed Biosynthetic Pathway их- он он но. va tic as er, -O O. 85. HOR OR 1 (R- H, B); 3 (R 2 (A- H, a); 4 (R Me, B); Me, a); zu,

Answer 1

Answer : (1) in image 1, reaction (2) :

Name of the reaction = alpha - alkylation of carbonyl compounds or alkylation of Enolate ion .

Since LDA is a strong base it will abstract alpha H⁺ and form Enolate , then Enolate attacks to alkyl iodide to form the product . (Note : since iodide is better leaving than OEt of ester so enolate would not attack on Carbonyl of ester ) .

Second picture 1st reaction : In this reaction , ring cyclisation takes place by the use of acid catalyst . So, this is acid catalyzed ring cyclisation reaction. Special name of this reaction is Nazarov reaction .

Second picture second reaction : In this reaction no acid catalyst or even no any catalyst is used , it is just intramolecular rearrangement reaction to form more stable compound from the least stable compound .