[74abbb]

Hello,
First of all sorry if my english is bad, I'm from France.
I'm trying to understand the synthesis of bryostatin 1 wich is an exceedingly scarce marine-derived natural product that is in clinical development directed at HIV/AIDS eradication.

I've understood the first steps but when they obtain a ketone and aldehyd, they said that they made a nokami's crotylation between the aldehyd and nokami's reagent to obtain a ketone and alcohol.I know it's difficult to visualise so please see attached a picture of the reaction.

I hope that someone can help me to understand the mechanism.

Thank you!

[clarkstill]

You can find the mechanism in this paper:

https://pubs.acs.org/doi/pdf/10.1021/ja011257f

The alcohol of the Nokami reagent adds to the aldehyde of your substrate generating an oxocarbenium intermediate. The alkene then does an intramolecular Prins-type nucleophilic addition (or maybe a pericyclic [3,3]-oxa-Cope type rearrangement).