The Diels-Alder Reaction

M
O	O	O	O	O
PhH, Rfx, 50%			S	AcOH, 43%
			73b

O	O				O
		O			O
S					S
				O
			+	80%	O
		S			S
				O	O
		77

N	N
N	N
Ph	Ph
78	79

M

M

MeO2C

O R

MA, PhH

Rfx, 24−60 h

80−82%

O O

O

O R

MP, PhMe, Rfx, 7 d,

12%

OMe

O R

80

R = H, Me

TCNE, CHCl3 r.t., 12−24 h

90%

NC CNCN

CN

MeO

O

BQ, PhMe, Rfx, 48 h, 32%

DMAD,

PhH or xylene Rfx, 5−72 h 25−33%

O

O R

MeO2C CO2Me

O R

O R

MP = methylpropiolate; BQ = 1,4-benzoquinone; MA = maleic anhydride; DMAD = dimethylacetylenedicarboxylate; TCNE = tetracyanoethylene

M

M

M

M

	R2		H O
	O	H	X
		R		X = O, N-Ph
		1 O
		MA or NPM,
		PhH, r.t.
		3 h, 60−80%
R2		R2			R2
H O	NQ,n-PrOH			TCNE, PhH, r.t.	CN
			R1		CN
O	r.t., 44%			0.5−1 h, 50−83%	CN
					O R1 CN
RH1		O
O		81

R1 = R2 = H, Me

MA = maleic anhydride; NPM = N-phenylmaleimide; NQ = 1,4-naphthoquinone; TCNE = tetracyanoethylene

O

O

S

BQ, AcOH,100 C 8 h, 51%

O						CNCN
	O				NC	CN
	NQ, n-PrOH		TCNE, THF,
S	r.t., 44%	S	0−25	C, 21 h,66%		S
		82

COPh

PhH, Rfx, 8 h, 54%

COPh

PhOC COPh

S

BQ = 1,4-benzoquinone; NQ = 1,4-naphthoquinone; TCNE = tetracyanoethylene

					M
X	Z	X					E	E
				R1
H	R1	Z			E	E	H	R1
		PhMe, MS 4A,	N	R		PhMe, Rfx,
N	R	Rfx, 7−40 h,	H		3−16 h, 20−46%		N	R
H		12−73%	83				H
			R = H, Me; R1 = H, Me, Ph
[1,3]-H shift							[1,3]-H shift
X	Z						− H2
	R1
N	R						E	E
H	O Ph O							R1
X-Z =		; X = H, Z = CO2Me
	N							R
							N

X = H, Z = CO2Et; X = Z = CO2Me

H

E = CO2Me

$ $

	CO2Me	CO2Me		CO2Me
		H	CO2Me	MeO2C
N		N		N
H		H
				H
H	CO2Me			! "
PhMe, MS 4A			CO2Me
Rfx, 5 d, 8%				− CH2=CH2
N		N
		H	CO2Me
H

M

N N

84

M

R1 R2				R1	R2
CO2H	acetone, Rfx				CO2H	HCl
N		82−99%		N	CO2H	Acetone		r.t.,
								84−96%
			O				R1 R2
O								H	O
				H
+		+	O
									O
R1				90−120 C, 3−18 h
N	R2			12−67%			N	H
			O
								O
R2					R1	R2
						H	O
R1
					N	H	O
						H
N						O

R1 = Me, Et, Ph, CH2COMe, p- and m-XC6H4 (X = Me, OMe, Br, Cl, F, NO, Ph) R2 = H, Me, Et, Bn, Me3CCOCH2

M

M

#

R2					R2		R2
	+	R*	DCM, MS4A			+
			18−120 h, 20−40
				C		R*			R*
N	O				N H		N	H
			2−24%
R1					R1 O		R1 O
					exo		endo
					R1	R2	exo/endo
	R* =	N			PhSO2	Me	> 99:< 1
					Me	Me	74:26
			SO2
					Me	Ph	> 99:< 1
					Me		> 99:< 1

N

M

M

O

O

BQ excess, 150 C, 22 h 25%

O

NQ	NPM, 150 C
50%	3 h, 40%

O

85

MA

NO2C6H5, 87%

O

O

O

N Ph

O

DDQ,triglyme, Rfx, 18 h 25%

	H	O
	H	N Ph
	H
	H	O

BQ = 1,4-benzoquinone; NPM = N-phenylmaleimide; NQ = 1,4-naphthoquinone; MA = maleic anhydride

M

1., DME

2.triglyme, Rfx, Pd/C, 30%

O
	O
1. excess O	, 150 C, 4.5 h
2. triglyme, Rfx, Pd/C, 30%
	O
	O
86
	O
1. excess	O , PhMe, Rfx, 18 h

2. triglyme, Rfx, Pd/C, 26%

O

M

M

M

M

M

M

M

Ph				Ph	Ph
+		r.t., −120 C		+		R1
		1−8 d, 40−92%
				NC N R1 NC
NC N	R1				N	! "
R				R	R
87	88
a, R = CO2Et	R1 = Ph, EtO, CO2Me
b, R = Ph
c, R = OMe

M

	OH		R	R
	R	Rfx		C60
				C60
		DCB
	NH		N	N	! "

89

R = Ph, 2-Th, p-MeOC6H4

	R					R
	N		1. PhMe, 25	C, 6−24 h	HN		N
		+	R2CN
R1
	N S		2. H2O, 80−91%		R1N	S	R2
								! "
	SiMe3
	90

R = Ph, 2-Th; R1 = Ph, p -ClC6H4; R2 = Ts, CCl3, CO2Me

M

			O S			O	O
		R1	S		R1	S
			O	S	O
					Py, CHCl3,
			Py, CHCl3,		r.t., 24 h,
			r.t., 63−64 h,		85% O
			79−89%		, R1 = Me
			O	O
					O
							O O
	O		O		S
R1			Py, CHCl3, r.t.,	R1	Py, CHCl3, r.t.,	R1	S
	S			O
			20−23 h, 88−97%	91, R1	= Me 2.5−17 h, 67−78%		O
	O
				92, R1	= OMe

M

	R			R
			Py, CHCl3, r.t. R1	O O
R1	O	O

+5−50 h, 58−87%

R2	S	R2		S
			R3	! "
	R3
	93

R = OH, OMe; R1 = Me, OMe; R-R1 = −(CH=CH)2−; R2-R3 = (CH=CH)2−; R-R1 and R2-R3 = −(CH=CH)2−

M