Very high 1,2- and 1,3-asymmetric induction in the reactions of allylic boron compounds with chiral imines

Imino‐Diels–Alder Reactions of 1‐Aryl‐3‐(trialkylsiloxy)‐1,3‐butadienes in Solution and the Solid Phase

“…[27] We applied the same reaction conditions as those used previously. However, after 30 h only a partial transforma-Scheme 6.…”

Stereoselective Synthesis of Hexahydroisobenzofuran‐4(1H)‐ones from Chiral Substituted Cyclohex‐2‐enyl Carbamates via Asymmetric Homoaldol Reaction and THF Cyclocondensation

“…[17] In contrast, the reaction of a cyclooctenyltitanium species with imines yielded addition products with anti-configuration, which was explained by a six-membered chair-like transition state in which the imine substituent occupies an axial position. [18] An anti selectivity was also observed in the reaction of a cyclic six-membered β-silyloxy-substituted allyltitanium compound with aldehydes. [19] The reaction of 13 with several aldehydes 12a-g yielded anti-cis-configured diastereomers 20a-g in good yields, but these were accompanied by up to 20 % of antitrans diastereomers 19a-g if the TMEDA complex of 2·Li was the intermediate (Scheme 4, Table 1, for an example see Entry 3).…”

C‐Selective and Diastereoselective Alkyl Addition to β,γ‐Alkynyl‐α‐imino Esters with Zinc(II)ate Complexes

“…[6] However, the desired C-methyl addition to 9 a did not proceed selectively. Instead, N-methylation-derived compounds were obtained in considerable yields (> 40 %) along with the desired 10 a (36 %).…”

“…[16] The excellent diastereoselectivity of the Calkyl addition products can be understood in terms of the well-known paradigms. [6] The bulky chiral 8-phenylmenthyl group would shield the re-face and promote the attack of the si-face exclusively (Figure 2). …”