Involving the Generation of Two Bonds 5.1. Introduction 5.2. Formation of the NÀC 2 and C 3 ÀC 4 Bonds 5.2.1. DielsÀAlder Related Reactions 5.2.2. Tandem Michael AdditionÀCyclization Sequence 5.2.3. Miscellaneous Reactions 5.3. Formation of the NÀC 2 and C 4 ÀC 4a Bonds 5.3.1. Michael Addition Initiated Reactions 5.3.2. Miscellaneous Reactions 5.4. Formation of the NÀC 2 and C 2 ÀC 3 Bonds 5.5. Formation of the C 2 ÀC 3 and C 3 ÀC 4 Bonds 5.6. Formation of the C 2 ÀC 3 and C 4 ÀC 4a Bonds 5.7. Formation of the C 3 ÀC 4 and C 4 ÀC 4a Bonds 5.8. Formation of the C 8a ÀN and C 4 ÀC 4a Bonds 5.9. Formation of the NÀC 2 and C 8a ÀN Bonds 6. Synthesis of 1,2,3,4-Tetrahydroquinolines Involving the Generation of Three or More Bonds 6.1. Formation of the NÀC 2 , C 2 ÀC 3 , and C 4 ÀC 4a Bonds: The Povarov and Related Reactions