CHAIRquizAns

# CHAIRquizAns - CH 3 CH 3 H 3 C H OH H Now complete the...

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HO H Easy Chair Complete the 6 (yes, 6) chairs for Compound A - each time you should start at a different C in the ring. DRAW BOTH AXIAL AND EQUATORIAL POSITIONS AT ANY RING ATOM THAT HAS A SUBSTITUENT (this is a general rule!) CH 3 CH 3 H 3 C H OH H CH 3 H H 3 C HO H 3 C H CH 3 H HO H 3 C H 3 C H CH 3 H H 3 C HO CH 3 Now identify the ones that are the SAME - meaning that they represent the SAME conformation, you are simply viewing the chair from a different perspective! H H 3 C CH 3 CH 3 H I chose to start here H 3 C H CH 3 OH CH 3 H H CH 3 CH 3 OH CH 3 H The three boxed are one set - the same groups are axial/equatorial on each. Another way of looking at it is that the substituted atoms are on the same type (UP or DOWN) of chair atom. The unboxed represent the CONFORMER of the boxed set, as in the other set, each of the three are identical (but viewed from a different perspective, but they represent a different conformation from the boxed set conformation - up atoms in one set are down atoms in the other
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Unformatted text preview: CH 3 CH 3 H 3 C H OH H Now complete the chair pair using the forms given (which represent the "flip" due to rotation). DRAW BOTH AXIAL AND EQUATORIAL POSITIONS AT ANY RING ATOM THAT HAS A SUBSTITUENT (this is a general rule!) CH 3 OH H H 3 C Use both methods above to draw the conformational chair pair for this! CH 3 H CH 3 HO H 3 C H CH 3 H H 3 C OH CH 3 H becomes "foot" "head" each up becomes down But NOTE that the positions of the groups attached to the ring with respect to the ring and to each other (i.e. wedge, dash, which is an absolute stereochemical arrangement) do NOT change! methyl is still above the ring and above H since it is now on a "down" carbon, the methyl is equatorial above the ring. Different start postion rotation or "flip" H H 3 C CH 3 OH CH 3 OH H CH 3 CH 3 OH H CH 3 CH 3 OH H H 3 C...
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## This note was uploaded on 01/28/2011 for the course CHEM 215 taught by Professor Koreeda during the Spring '07 term at University of Michigan.

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