Stereoselective addition reactions to chiral N-benzylidene-p-toluenesulfinamides. Application to the synthesis of optically active 1,2-diphenylethylamines

Short asymmetric synthesis of (S,S)-PDP using l-prolinol derivative as economic starting material

“…Grignard reagent containing acetal protecting groups were usually well tolerated, and gave a high yield and diastereoselectivity in the nucleophilic additions. 9 However, our initial attempts in the nucleophilic addition of freshly prepared BrMg(CH 2 ) 3 OEE (14) 10,11 to sulfinylimine 12 in THF at À48 C resulted in two inseparable diastereoisomers 15a and 15b. The ratio of these two isomers could be determined by HPLC.…”

Stereocontrolled reactions mediated by remote sulfoxides: Formation and reactivity of enantiomerically pure benzylic centers

“…The nucleophilic addition of many alkyl and arylmetals to N-sulfinylimines is one of the most straightforward and attractive routes to prepare chiral amines in high yields with good stereoselectivities. However, benzylation of the N-sulfinylimines usually proceeded with moderate and erratic stereoselectivity [18], always lower than 75% de's from N-p-toluenesulfinylimines and slightly higher in some cases with N-t-butanesulfinyl derivatives. Moreover, there was no report on the use of prochiral benzyl carbanions, which would provide 2-arylethylamines with the simultaneous formation of two chiral centers.…”

Stereoselective Synthesis of α‐Branched Amines by Nucleophilic Addition of Unstabilized Carbanions to Imines

“…Although the p-tolylsulfinyl group 31 has been sporadically used for the addition of Grignard reagents, the transformation generally suffers from an important side reaction resulting from an undesired attack of the nucleophile on the electrophilic sulfur atom [50] (Scheme 1.13).…”

“…As seen in Scheme 1.14, exceptions to this are when benzyl- [50], allylmagnesium chloride [51], vinylaluminum [52,53], or vinylcopper reagents are used as nucleophiles [54].…”