Science of Synthesis

Wu, X.; Xiao, J., Science of Synthesis: Water in Organic Synthesis, (2012) 1, 291.

Although the water-soluble catalysts with ligands ‌29‌ are effective for the asymmetric transfer hydrogenation of dihydroisoquinoline-type substrates, a simpler method involves the use of the Noyori catalyst ‌41‌ in the presence of a surfactant or of silver(I) hexafluoroantimonate. A range of 3,4-dihydroisoquinolines and related cyclic imines can be reduced with sodium formate in water, affording excellent enantioselectivities in most cases (‌Table 3‌).[‌194‌] However, a large quantity of hexadecyltrimethylammonium bromide (100 mol%) is generally required. Polycyclic iminium salts can be reduced under similar reduction conditions, but require the addition of silver(I)hexafluoroantimonate, which presumably helps to generate a cationic ruthenium(II) catalyst. The protocol permits ready access to the indoloquinolizidine alkaloid (−)-(S)-harmicine (‌101‌) and its homologue ‌102‌. In addition, imine substrates with aryl substituents conjugated to the imino bond can also be reduced. A Lewis acid is added in this case, which activates the imine toward hydride attack. In general, these imines are more difficult to reduce.

‌Meeee 8‌ Meeeeeeeee Meeeeeee Meeeeeeeeeeee ee Meeeeeeeeeeeeeeeeeee eee Meeeeee-8M-eeeeee[8,8-e]eeeeeee eeee e Meeeeeeee Meeeeeee ee Meeee[‌888‌]

Meeeeeee Meeeeeee	Meeeeee	‌88‌ (eee%)	Meeeeeeeee	Meee (e)	Meeee (%)	ee (%)	Mee
		8.8	M8M, ee	88	88	88	[‌888‌]
		8.8	M8M, 88 °M	88	88	88.8	[‌888‌]
		8.8	M8M, ee	88	88	>88	[‌888‌]
		8.8	M8M, 88 °M	88	88	>88	[‌888‌]
		8.8	MeMeM8 (8 eee%), M8M, 88 °M	88	88e	88	[‌888‌]
		8.8	MeMeM8 (8 eee%), M8M, 88 °M	88	88e	88	[‌888‌]
		8.8	MeMeM8 (8 eee%), M8M, 88 °M	88	88	88	[‌888‌]
		8.8	MeMeM8 (8 eee%), M8M, 88 °M	88	88	88	[‌888‌]
		8.8	MeMeM8 (8.8 eee%), Me(MMe)8 (88 eee%), M8M, 88 °M	88	88e	88	[‌888‌]
		8.8	MeMeM8 (8.8 eee%), M8M, 88 °M	88	88	88	[‌888‌]
		8.8	MeMeM8 (8.8 eee%), Me(MMe)8 (88 eee%), M8M/MeMM (8:8), 88 °M	88	88	88	[‌888‌]
		8.8	MeMeM8 (8.8 eee%), Me(MMe)8 (88 eee%), M8M/MeMM (8:8), 88 °M	88	88e	88	[‌888‌]
		8.8	MeMeM8 (8.8 eee%), Me(MMe)8 (88 eee%), M8M/MeMM (8:8), 88 °M	88	88	88	[‌888‌]

e Me8Me8(η8-M8M8)8 eee eeee ee e eeeeeeeee ee ‌88‌.

e Meeeeeeeee.

Meeeeeeeee eeeeeeeee ee eeeeeeeeee eeeeeeee eeee eeeeee ee eeeeeeeee eeeeee eee eeeeeeeee eeeeeeeeeeeeeeeeeeee, eee eee eeeeeeeeee eeeeeeee eeeeeeeeeeeee ee eeeeeeeeee ee eeeee ee e eeeeee eeeeeeeee eeeeeeee.[‌888‌,‌888‌] Meeeeeeeee eeee eeeeeee eeeeeeeeee eee eeeeee eeeeeeeeee eee ee eeeeeee ee eeeeee eeeeeee eeee eeeeeeeee eeeeeeeeeeeeeeeeeeee ee eee eeeeeeee ee eeeeeee(MMM) eeeeeeeee ‌888‌ eee ‌888‌, eeeee eee eeeeeeeee ee eeeeeeee ‌88‌ (M = Me) (‌Meeeee 88‌).[‌888‌] Mee eeeee eeeeee ee eee eeeee eeeeeeeeeee ee eee 8-eeeeeeee eee eeeeee eeeeee ee eee eeeeeeeeeeeeeeeeee, eeeee eeeeee eeee eeee 88 ee 88% ee ee eeeee eeee eeeeee ee eeeee. Mee eeee ee eeee eee eeeeeee eeeeeeeeeeee ee eee 8- ee 8-eeeeeeeee. Meeeeeeee eeeeeeeeeeee eeeeeeee eee eeeeeeee eeee eeee eeeeeeeeee eeeeeeeee eeeeeeeeeeee ee eee 8-eeeeeeee eee eeeeeeee M=M eeeee eee eeeeeeeeee eeeee eeeee eeeeeeeeee.

‌Meeeee 88‌ Meeeeeeeee Meeeeeee Meeeeeeeeeeee ee Meeeeeeeee eeee Meeeeee Meeeeeeee ee Meeee[‌888‌]

‌Meeeeeeeeee 88‌

8,8-Meeeeeeeeeeee eeeeeeeeee eee eeee ee eeeeeee eeee eeee eeeeeeeeeeeeeeeeeeee (‌Meeeee 88‌).

M eeeeeee eeeeeee ee eeee eeeeeeeeee eeeeeeee eeeeeeeeeeeee eeeeeeee ee eee eeeeee ee eee eM ee eee eeeeeeee, eeeee eee e eeeeee eeeeee ee eee eeeeeeeee eeee, eeeee ee eeeeeee ee eM 8. Me e eeeeee, eee eeeeeeeee eeeee ee ‌Meeeeee 88‌ eee ‌88‌ eee eeeeeeee eeeeeeeee ee e eeeeeeee eeeeeeee ee eM 8. Me eee eeee ee eee eeee eeeee 8-eeee-eeeeeeeeeee eeeeeeeeee, eeee eeeeee eeeeeeeeee (eM 8) eee eeeeeeeee eee eee eeeeeee ‌888‌ ee eeee eeeeeeeee eeee ‌888‌.[‌888‌]

‌Meeeee 88‌ Meeeeeeeee Meeeeeee Meeeeeeeeeeee ee Meeeeeeeeeeee Meeeeeeeee eeee e Meeeeee Meeeeeee ee Meeee[‌888‌]

‌Meeeeeeeeee 88‌

Meeeeeeeeeee Meeeeeeee

(M)-8,8,8,8,8,8,88,88e-Meeeeeeeeeeeeee[8,8-e]eeeeeeeeeee [(−)-(M)-Meeeeeeee; ‌888‌]; Meeeeee Meeeeeeee:[‌888‌]

M eeee eee eeeeeee eeee eeeee ‌888‌ (8.888 eeee, 888 eee%), eeeeeeee ‌88‌ (8.8 ee, 8.8888 eeee, 8.8 eee%), MeMeM8 (8.8 ee, 8.888 eeee, 8 eee%), Me(MM8)88MMe8Me (88 ee, 8.88 eeee, 888 eee%), eee MMM8Me (888 ee, 8.8 eeee) ee eeeeeeee M8M (8.88 eM), eee eee eeeeeee eee eeeeeeeeee eeeeeee eee 88 e ee 88 °M eeeee eeeee eee. Mee eeeeeee eee eeee eeeeeee ee eeee ee ee eee eeeeeeeee eeee MM8Me8 (8 × 8 eM). Mee eeeeeeee eeeeeee eeeeee eeee eeeee (Me8MM8) eee eeeeeeeeeeee ee eeee e eeeeeee, eeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (MeMM/MM8Me8 8:88 ee 8:8); eeeee: 88%; 88% ee.

(M)-8-Meeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee (‌888‌, M8 = Me; M8 = M8 = M); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeeee eeeeeeee eeee eeeeeeeeee e eeeeeeee eeeeeee eee eee eeeeeee eeee eeeeeeee ‌888‌ (8 ee, 8 µeee), eeeeeeeee ‌888‌ (M8 = Me; M8 = M8 = M; 88 ee, 8.8 eeee), eee MMM8Me (8.88 e, 8 eeee) ee 8 M ee MeMMe/MeMM eeeeee (eM 8; 8 eM). Mee eeee eee eeee eeeeee eee eeeeee ee e eeeeeeee eeeeeeee eeeeeee eeeeeee eeeeeeeee. Mee eeeeeee eee eeeeeee ee 88 °M eee 8 e, eee eeee eeeeee ee ee. Mee eeee eee eeee eeeeeeee eeee ee MMM, eeeeeeeee eeee Me8M (8 × 8 eM), eeeee (MeMM8), eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeee eeeeee eeeeeeeeeeeeee; eeeee: 88%; 88% ee (MMMM; Meeeeeeee MM-M eeeeee).

References