Strategy appendage-based

Appendage based strategies may be divided into disconnective and reconnective. The latter may be further partitioned into ring appendage - ring 

ACS Symposium Series American Chemical Society Washington, DC, 1977. 

THE CHEMISTRY PACKAGES OF LHASA Functional Group Based Transforms 

Two group transforms are keyed specifically by two functional groups with a path of predetermined length between them. Examples of these are shown below. 

One group transforms are similar but are keyed by one specific group with an associated path (not as 

---

The synthesis of ovalicin was accomplished following a line of analysis which was totally different from that employed for the synthesis of the structural relative fumagillol. The plan for ovalicin was based on S-goal, appendage, stereochemical and functional group derived strategies. A key requirement for the synthesis was the stereospecific construction of the -l,4-pentadienyl subunit, which was achieved by a method of potentially wide utility. 

Cyclopentene derivatives with unsaturated appendages are also available via this general annulation strategy representative examples are presented in Scheme 15. In these several transformations desulfonylation is achieved using base-induced -elimination, via the fluoride-promoted elimination of 3-silyl sulfones, and by means of Brook rearrangement chemistry according to the method of Reich. In summary, a wide variety of complex functionalized cyclopentenes are available using this versatile [4 1]... 

E. J. Corey and W. L. Jorgensen, Computer-Assisted Synthetic Analysis. Synthetic Strategies Based on Appendages and the Use of Reconnective Transforms , J, Amer. Chem. Soc., 1976, 98, 189. 

The metal-based preparations of conjugated dienes represent the majority of the strategies employed to attain stereoselectively 1,3-dienes connected to aryl and/or alkyl appendages. The starting material can be stereodefined when double bonds or enynes are engaged. When alkynes or allenols are employed, two double bonds are generated in a stereoselective manner. 

The one-pot preparation of (Z, )-2,5-dienol was described by Walsh in 2006 [1]. The strategy is based on the sequential functionalization of bromo-substituted 1,3-enynes such as 4-bromo-l,3-enyne 1 by hydroboration followed by hydride addition to the resulting borane (steps i and ii in Scheme 1). Next, dialkylzinc and carboxaldehyde (steps iii and iv) were sequentially introduced to complete the formal addition of (Z)-dienyl group to an electrophile. The two aldol products 2 and 3 are illustrative of the potential of this methodology. These products contain both (Z)-olefin and thiophen or triple bond appendages and could, with difficulty, be prepared by conventional Lindlar reduction due to risks of catalyst poisoning by the thiophen moiety or over reduction of the triple bond. 

---