Lect23_031010.ppt

Reading for Wednesday Chapter 21: 21.7-21.13 Moon?s 11-noon office hours are cancelled today ARIS Quiz #4 Available Today Due Monday night, March 22, at midnight Discussion sessions for THIS week: Monday 4:30-6:30 pm (2001 Malott) (+) Tuesday 4-5 pm (2005 Malott) Wednesday 4-5 pm (2005 Malott) Saturday 11 am-1 pm (2001 Malott) (+) Chapter 21 Aldehydes and Ketones: Nucleophilic Addition If CHO bonded to a chain of carbon atoms: Identify longest chain containing CHO group Replace ?e in parent with ?al Assign carbonyl carbon position 1, but omit this number from the name IUPAC Nomenclature of Aldehydes (21.2A) If CHO bonded to a ring: Name the ring and add the suffix -carbaldehyde Assign carbon bearing the -CHO group position 1, but omit this number from name IUPAC Nomenclature of Aldehydes (21.2A) Acyclic Ketones: Identify longest chain containing C=O group Replace ?e in parent with ?one Number to give C=O carbon the lower number IUPAC Nomenclature of Ketones (21.2C) Cyclic Ketones: Replace ?e in parent with ?one Assign C=O carbon position 1, but omit this number from the name IUPAC Nomenclature of Ketones (21.2C) Common Names of Ketones and Aldehydes (21.2B,D) Know These! Preparation of Aldehydes: (21.6) A Review Preparation of Ketones: (21.6) A Review Overview of Nucleophilic Addn. Rxns. (21.7) Overview of Nucleophilic Addn. Rxns. (21.7) Elements of H-CN added across C=O bond Product is a cyanohydrin Treatment of a cyanohydrin with base releases -CN Nucleophilic Addition of -CN (21.9) Some plants contain cyanohydrin precursors Cassava Root C=O converted to C=C Wittig reagent (an ylide) is an organophosphorus compound Mixtures of E/Z isomers can form; cis- often favored over trans- using the classic version of the reaction (i.e. the one we are studying). The Wittig Reaction (21.10) Capsaicin What makes peppers HOT Application of the Wittig Reaction In this example, trans alkene is formed because the ylide is stabilized via conjugation