organic chem 2 bible

organic chem 2 bible - CHM 2120 Summary posting 2009 THIS...

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CHM 2120 Summary posting 2009 THIS POSTING CONTAINS 1. A LISTING OF COMMON REAGENTS 2. SPECIAL ‘SITUATIONS’ THAT HAVE UNUSUAL REACTIVITY 3. pKa SCALE THAT COVERS ALL OF THE KEY FUNCTIONAL GROUPS THAT WE HAVE MET IN THE COURSE. Common Reagents: a) NaH ; A 'PURE BASE' ALWAYS TIES TO FIND AN ACIDIC HYDROGEN, generally an O-H or N-H b) A lCl 3, STRONG LEWIS ACIDTHEAT COMPLEXES WITH R-Cl TO GENERATE A CARBOCATION. THINK FRIEDEL CRAFTS. c) FeCl 3 ;a WEAKER LEWIS ACID THAN IS ALUMINIUM TRICHLORIDE. USED IN CONJUCNTION WITH Cl 2 TO CHLORINIATE AROMATIC COMPOUNDS, SIMILARLY Br 2 /FeBr 3 d) Na BH 4 ; A REDCUING AGENTTHAT SUPPLIES NUCLEOPHILIC HYDROGEN, REDUCES KETONES AND ALDEHYDES TO ALCOHOLS, REACTS WITH CARBOXYLIC ACIDS TO GIVE H 2 and the SODIOUM SALT OF THE ACID. e ) k) L iAlH 4 ; A MORE POTENT REDUCING REAGENT THAN NaBH 4. REDUCES ESTERS AND CARBOXYLIC ACIDS TO PRIMARY ALCOHOLS. REDUCES NITRO COMPOUNDS TO AMINES f) s odium dichromate; o) chromic acid. POTENT OXIDIZING AGENTS. WHEN USED ON A PRIMARY ALCOHOL IN THE PRESENCE OF WATER, THE RESULT IS A CARBOXYLIC ACID. Secondary alcohls are converted to ketones g) C rO 3 /pyridine; A OXIDIZING AGENT. WHEN USED IN THE ABSENCE OF WATER CONVERTS PRIMARY ALCOHOLS TO ALDEHYDES. Secondary alcohols are converted to ketones h) KMNO 4 ; A POTENT OXIDINING AGENT. CONVERTS ALKENES TO cis 1,2-DIOLS UNDER MILD AQUEOUS CONDITIONS; OXIDIZES AROMATIC SIDE CHAINS TO CARBOXYLIC ACIDS, IF THE SIDE CHAIN CARBON HAS AT LEAST ONE BENZYLIC HYDROGEN. i) dibenzoyl peroxide; A SOURCE OF PEROXY RADICAL, USUALYY A RADICAL CHAIN INITIATOR OR DI-tert--BUTYL PEROXIDE , does the same job. j ) N-Bromosucciimide [NBS ] WHEN IN COMBINATION WITH PEOROXIDE INDICATES FREE RADICAL BROMINATIONS;preferably at benzylic or allylic positions k) Peracetic acid CH 3 C(O)-O-OH ; also meta chloroperbenzoic acid [MCPBA] OXIDIZING AGENTS .CONVERT ALKENES INTO EPOXIDES l ) N a( +) (-) CN, AN EXCELLENT NUCLEOPHILE AND A VERY WEAK BASE. TENDS TO GIVE ONLY SN 2 REACTIONS IF A SUITABLE LEACING GROUP IS PRESENT m , Li (+) (-) SR, ; THE THIOLATE ANION IS A POTENT NUCLEOPHILE. IT IS MUCH BETTER AS A NU THAN THE CORRESPONDING NEGATIVELY CHARGED OXYGEN SPECIES BUT ALSO A WEAKER [BY 10 6 BASE
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n) s odium methoxide; A BASE AND A NUCLEOPHILE, VERY MUCH THE SAME WAY AS HYDROXIDE ION. o) s odium carbonate; A RATHER WEAK BASE OFTEN USED AS PART OF THE SYSTEM TO GET AN E 1 REACTION, OR SIMPLY TO NETRUALIZE STRONG ACIDS. p) potassium tert butoxide; A STRONG HIGHLY HINDERED BASE . THE pKa OF THE CONJUGATE ACID IS 19 THUS STRONGER THAN HYDROXIDE BUT NOT NEARLY AS STRONG A BASE AS IS LDA . IN ADDITION TO APPROPRIATE ACID BASE REACTIONS THIS REAGENT TENDS TO SIGNIFY THE POSSIBILITY OF AN E 2 REACTION q) lit hium diisopropyl amide [LDA] ; A VERY STRONG HINDERED BASE THAT TENDS TO ACT ONLY AS A BASE. STRONGER THANT POTASSIUM tBUTOXIDE SINCE THE pKa OF THE CONJUGATE ACID IS MORE THAN 35. USEFUL FOR THE QUNATITATIVE GENERATION OF ENOLATES FROM KETONES AND ALDEHYDES and ESTERS and AMIDES by removing selectively an alpha hydrogen. DEPENDING ON
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organic chem 2 bible - CHM 2120 Summary posting 2009 THIS...

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