Extension of side chains

Methods of Introducing Side Chains. The side chains introduced in the total synthesis of steroids must be sterically oriented in a suitable manner and contain functional groupings providing for subsequent cyclization. Table 3 gives an idea of the use of various methods for the building up and extension of side chains. According to this table, the main reactions involved are organometallic syntheses, the Michael reaction, and various alkylation reactions. 

Table 3. Main Methods for the Formation and Extension of Side Chains Used in Total Steroid Syntheses...

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