Six-membered ring synthesis

The Norrish-Yang reaction, with the spin-center-shift extension, facilitates access to a variety of cyclic compounds. This will be discussed here, with examples of the synthesis of three- to six-membered rings synthesis of macro- and bicydic compounds and the photochemistry of imides will not be covered. The examples especially demonstrate the capabilities of the reaction with regard to stereoselectivity. 

Enolate D of Figure 13.73 undergoes an aldol condensation with the C=0 double bond. The enone A is the condensation product. This reaction represents a six-membered ring synthesis even though it is not a six-ring annulation. 

Six-membered Ring Synthesis by Formation of Two Bonds 4.05.4.3.1 From [5+1J atom fragments... 

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