Catalytic Asymmetric Addition of sp Hybridized Carbanions

An enantioselective copper catalyzed addition of alkynes to enamines was reported 

42 J Stereoselective Synthesis of a Branched Amines by Nucleophilic Addition 

The importance of a branched chiral amines in nature and as substructures in biologically active unnatural products led to the rapid development of an impressive number of methods to synthesize this class of compounds in enantiomerically enriched forms. It is quite spectacular to see how many very efficient methods have appeared since the early twenty first century. Furthermore, catalytic asymmetric methods now exist to transfer sp , sp, or sp nonstabilized carbanion nucleophiles to a wide range of activated imines. Even if the past 10 years have witnessed phenomenal advances in this area, Ellman s chiral auxiliary method is still very attractive. Indeed, it is the only one that allows the addition of the three kinds of nucleophiles using the same dass of reagents and it also possesses numerous other 

The cryptostylines and their analogues have been used as pharmacological probes, such as the Dj dopamine receptor, an antagonist of substance P, and a peptide neurotransmitter. Propose a catalytic asymmetric synthesis of (S) (+) cryptostyline II starting from methyl 2 (2 formyl 4,5 dimethoxyphenyl)acetate and 4 bromo 1,2 dimethoxybenzene. 

Propose a mechanism for the following formation of the aza Morita Baylis Hillman reaction product that is obtained from an a hydroxypropargylsilanc (1) and the N tert butanesulfinyl imine. Provide the structure of intermediate A obtained upon slow addition of n BuLi to ( ) 1. 

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