The ketone A was subjected to a reaction with LDA at -78 °C, followed by addition of isobutyraldehyde (Scheme). Provide the product B, including the stereochemistry at all relevant stereogenic centers. Show the mechanism of the reaction and draw a transition structure that clearly indicates how the stereoisomer is formed. A 1. LDA, -78°C 2. H B

2. Analyse the reaction scheme below and provide structures/reagents used from A-F. LL NH3 H₂O A HCI OH D+ E Heat NH₂ B+C

Propose structure(s) for the main organic product(s) formed in each of the following reactions (show stereochemistry of the product where necessary).

Provide the structure of the major organic product of the following reaction and? explain the stereochemistry which results in this product. 2-Pentanol reacting with 1.) PBr3, pyridine 2.) NaCN

What epoxide and organometallic reagent are needed to synthesize each alcohol below? Pay close attention to the correct representation of stereochemistry, where appropriate. 3. (а) "OH desired ерохide organometallic reagent product (b) H но desired product ероxide organometallic reagent 4. A CHEM 245 student wants to synthesize some ethylene glycol to use as antifreeze in his radiator this winter. He proposes the following reaction to his instructor, who quickly explains that this reaction won't work as proposed due to the student's choice of reagent. 1) NaH 2) H2O OH Но a) Why can't sodium hydride (NaH) be used as the nucleophile in the reaction above? b) Propose an alternate reagent that COULD be used with the ethylene oxide to successfully give the desired ethylene glycol product.

Suggest a mechanism for the following synthesis. Draw and name each step.

Provide a 3-5 step synthetic route the target molecule from starting material A. Be sure to account for relative stereochemistry and to suggest reagents/conditions for each step CN .CI H3C CN Target molecule starting material (A)

Name the type of reaction and provide a possible reagent  assign all the stereocentres found in the compounds via cahn ingold prelog rules define the relation between compound. D E F G identify the 2 stereoisomers likely to be formed in compound c