Using the trans effect sequence given in the text, devise rational procedures for selectively synthesizing each of the three isomers of [Pt(py)NH3NO2Cl].

• 1. The HCo(CO)4 complex can catalyze the isomerization of pure cis-2-butene to a mixture of cis-2-butene, trans-2-butene, and 1-butene. Propose a mechanism. Carefully show the process using wedges and dashes to indicate stereochemistry of each intermediate.

There are four dimethylcyclopropane isomers. (a) Write three-dimensional formulas for these isomers. (b) Which of the isomers are chiral? (c) If a mixture consisting of 1 mol of each of these isomers were subjected to simple gas chromatography, how many fractions would be obtained and which compounds would each fraction contain? (d) How many of these fractions would be optically active? tod o ors brie page 10 of 17

1)Chemistry students are taking an experimental course in organic chemistry at a public university. During an experiment involving conjugated dienes, some doubts arose when discussing the results obtained so far: (a) A student obtained two products from the reaction of 1,3-cyclohexadiene with Br2. His lab partner was surprised to get only one product from the reaction of 1,3 - cyclohexadiene with HBr. Explain these distinct results.   (b) One student, seeing the discussion of colleagues, commented that she obtained two distinct products when reacting 1,3,5-hexatriene with HBr, with different yields just by changing the reaction temperature. Explain the results she obtained using reaction mechanism and based on kinetic and thermodynamic control involving conjugated dienes.

can you explain what regioselective, stereoselective, and enantioselective are, and how these all relate to each other in organic chemistry?

1. Arrange in order of decreasing acidity: i (a) CH₂CH₂NO, (CH₂)2CHCPh, CH₂CH₂CN, CH₂(CN)₂ [(CH3)₂CH)₂NH, (CH3)2CHOH, (CH3)2CH₂, (CH3)2CHPh (b) 0 CH₂CCH₂CO₂CH₂, CH₂CCH₂CCH₁, CH₂OCCH₂Ph, CH₂COCH₂PH CHSCO,CH, CHỈ KỊCHI, CỐCH, ÍCH,C CHICHIA PhCCH₂Ph, (CH₂)CCCH₁, (CH₂)CCCH(CH3)2, PhČCH₂CH₂CH₂ (c) (d)